It's time to tackle an issue which concerns almost all Virginia Hills residents, the problem of marine clay. In this article, I'll talk about what marine clay is, what problems it can cause, and how you recognize them. In the next issue, I'll talk about how marine clay problems should be fixed.
Millions of years ago, this part of Virginia was part of the Atlantic Ocean. Rivers flowed into the ocean, carrying with them silts and clays from upstream, and deposited them along the shoreline in the brackish waters there. As the ocean receded, these became the land on which our houses rest today. The soil deposits are known as marine clay. Marine clay soil may be bluish-gray, red, or yellow. While Fairfax County has some maps of marine clay, the only way to know for sure if you have it in your lot is to have a soils engineer conduct tests.
The problem with marine clay is that it is a shrink-swell type of soil. When the weather is dry, the water goes out of the clay, and it shrinks. When the weather is wet, the clay swells with tremendous force. This cycle continues year after year, occurring when rainfall is as little as five inches below normal. Let's look at how this can effect your house and yard.
Footings are those wide pieces of concrete at least 24 inches under your house which support the house's weight. If the footings rest on marine clay, when the clay shrinks, voids will develop under the footings, and eventually the weight of the house will cause the footings to settle, producing the characteristic "step-crack," so-called because it looks like a set of stairs, at the corner of your house. This can happen to a house with a basement, or to a house built on a slab.
In new construction where marine clay exists, footings are constructed much deeper than the usual 24 inches for the frost line. By placing the footings 6-8 feet below the surface, the builder insures that they are below the level of severe moisture changes in the soil. They are also reinforced with rebar to insure that if a small void develops the rest of the footing will carry the entire load.
A problem only for houses with basements, marine clay can cause serious horizontal cracking of the basement or foundation walls. When the clay swells, it exerts strong pressure pushing in against the basement wall. At some point the wall will crack. You can measure the amount of the swell by taking a long board and holding it up against the wall vertically, using a level to make it plumb. When the board touches in the middle of the wall, you'll see that it is an inch or more away from the top and bottom of the wall. I've seen this gap be three inches or more. At some point, the wall will fail and in a worst case scenario, will fall in, threatening the side of the house.
In new construction, this problem is avoided by several methods. First, a 4-8 foot wide backfill along the sides of the house is made up of material such as sand and gravel which, when compressed, will rise upward rather than push against the basement wall. Marine clay is kept away from this backfill with the use of a geotextile cloth through with it cannot penetrate. Second, drain tile (a pipe with holes in it) is laid along the base of the foundation to collect any water that accumulates there and conduct it away from the house. The drain tile is also wrapped with geotextile cloth to allow only the water to get into the pipe. Finally, large trees, whose roots can take moisture out of the soil and cause it to shrink, are not planted near the house.
Marine clay soils are slow to drain because the water tends to collect in flat areas. The way to avoid this problem is to maintain a positive drainage slope away from the house itself.
A more serious problem is with steep slopes such as are common in Virginia Hills. In the worse case, landslides (mud slides) can occur when the soil is completely saturated with water, though more often the movement is very slow, less than an inch per year. These movements often occur when homeowners attempt to do their own grading of the slope or install a retaining wall improperly. (Anything over two feet high requires a County permit).
Next time, we'll talk about fixing problems you already have with marine clay. The bad news is that these fixes are never simple and almost always expensive.
In Part I, we talked about what marine clay is and the problems it could cause. We discussed how new construction methods deal with the potential for these problems. This time, we'll talk about what to do it you've discovered that you have one of these marine clay problems. This is an update of the Part II I wrote in the fall of 1999. New technology, carbon fiber straps and elastomeric coatings, give you another, and potentially less expensive, alternative for repair.
This is still generally not work you can do yourself.
If marine clay under the footings at a corner of your house has shrunk and caused that part of the footing to drop, you'll see the classic "step crack" in the wall above it. Patching of the step crack will only hold until the next shrink-swell cycle. Real repair is accomplished by digging out the footing, often to a depth where no marine clay is present, and rebuilding the footing with rebar to allow adjacent areas of the footing to support each other. Depending on how badly the wall above the footing has cracked, you may have to have the contractor rebuild that portion of the wall. This often happens on a corner of the house.
If your house is built on a slab, you may be able to defer this repair for a long time if there is no serious drop. If the house has a basement, the resulting cracks may allow water to pour through the walls and may require immediate attention.
The symptom here is a horizontal crack near the middle of a basement wall where the pressure of the swollen clay has bowed the wall in until it cracked. Ultimately, the wall can break in the middle and your house would fall down into the basement. Long before that happens, however, you will experience serious water leaks through the cracks and notice obvious bowing inward.
The first step is to determine how far inward the wall has bowed. If the bow is much more than an inch, you will almost certainly have to rebuild that portion of the wall. That will involve digging away the dirt outside the basement and supporting that portion of the house while the wall is rebuilt. This is obviously a VERY expensive solution.
If you can save the wall, there are two solutions, neither of which is inexpensive. Formerly, one solution was to install steel beams vertically to hold the wall in place. A newer solution is to use carbon fiber straps instead of steel beams. Depending on your situation, the contractor will install a perimeter drain inside the basement and connect it to a sump pump. The contractor then pours a 4" concrete ledge over the drain along the floor of any wall being repaired and attaches the vertical carbon fiber straps every four feet to halt the minor buckling of that wall. Epoxy can be injected into the wall to remedy water problems and the concrete block can be sealed on the inside of the basement with an elastomeric coating.
Since you can frame on top of the ledge, the disadvantage of the loss of basement space to steel beams goes away.
The second alternative involves excavating outside the affected parts of the basement walls, temporarily supporting the house above, and tearing out the concrete block anywhere it is seriously bowed inwards. That portion of the wall gets rebuilt. Outside, perimeter drain is laid around the house at the footing level and gets run "to daylight" or to a sump pump so it will remove water from that wall's vicinity. The rebuilt basement wall is waterproofed on the outside. Finally, the perimeter is filled with a non-clay material, usually sand or gravel, that, when pushed on by the clay soil, will rise to relieve the pressure and then can fall back if the clay shrinks. A clay cap of a few inches is placed over the sand and gravel to keep water from running down into the sand and gravel. Of course, if you'd like a patio on that side of the house, a brick and concrete cap would work also.
Gutters should be kept clean so they don't overflow and downspouts should be directed away from the house.
Hearing the description of these two alternatives, you can imagine that the problem isn't inexpensive to fix. Depending on the amount of damage, such a project can run upwards of $30,000.
If you have to rebuild a portion of your basement wall, you might consider adding a large window and an escape window well to allow you to construct a legal bedroom in that portion of the basement.
A bowed retaining wall probably can't be fixed. It will almost surely have to be rebuilt. Depending on the height, you may need a permit from the County to do so. To prevent the bowing from recurring, you may need to use special backfill behind the wall and install a drainage system as described in the section on foundation walls.
Copyright Doug Boulter, 2011
Spring is coming! With Spring, we can look forward to the Spring rains. For some Virginia Hills homeowners, that may mean water in the basement.
There are two causes of wet basement problems. The most common is water from the surface running down along the side of the house and into the basement through the concrete block walls. The second problem is a basement built very close to the ground water table. When the water table rises, as it often does after a rain, the basement essentially becomes a boat riding on the ground water. Since the first cause produces most of the wet basement problems and is easiest for a do-it-yourselfer to fix, it will be the focus of this column.
Even though dams and pools are made from concrete, it is a very porous material, especially in the form of hollow concrete block. Water under pressure will eventually work its way through the concrete block, or through any cracks in the mortar that holds the block together. In the 1950s, coatings were applied to the outside of the block to "waterproof" it. At the same time, however, contractors often disposed of construction debris by using it to fill along the foundation. Over the years, the lumber in the debris rotted and the ground sank. During a rain, water gathers in the low areas and flows down the foundation looking for the path of least resistance.
Whether the basement is finished or only used for storage, the water will cause problems with dampness, and will hurt the resale value of your house. Fortunately, solving a wet basement problem may not be the very expensive project you have been dreading.
The first step is to keep rainwater away from the foundation. Often, overflowing gutters saturate the ground, and cleaning them will make the problem disappear. A second cause of water near the foundation is a downspout that empties too near the house. The equivalent of the rain falling on half the roof gets dumped at the foundation and forces its way in. Adding an extension to the down spout so that the water is discharged 10' away from the house may solve the problem.
However, if the ground slopes back toward the house, it will attract water. To check, take a straight 8' piece of 2x4 lumber and a level. Place the 2x4 pointing away from the house and check with the level to see if the ground does slope away, and if there are any depressions. Add fill dirt so there is a good slope and no depressions remain. Work around the house checking about every 6", filling as necessary.
Next, check for large shrubs or trees near the spot of the leak. Often roots can serve as a pathway for water to the foundation. Remove any offenders and fill to obtain proper slope.
If none of these solutions achieve the desired results, you may require professional help. In a future column, I'll write about damp-proofing the basement.
In my previous article, I discussed common causes of wet basements. I said that more than 90% of wet basements result from surface water running down the foundation walls. You can often stop this by cleaning gutters, extending down spouts, and regrading the soil around the perimeter of the house so that it slopes away from the foundation walls.
If these simple fixes don't remedy the problem, it's time to look further. Most Virginia Hills houses have basement walls made of concrete block. Inspect the blocks to see if any cracks have developed in the blocks themselves or in the mortar joints. If you find any, watch them closely to determine if they are the source of the leak. Also look carefully at the point where the concrete block meets the cement floor.
If water seems to be coming in at a crack at a mortar joint or where the block meets the floor, you can attempt to patch with hydraulic cement. This is a type of mortar which will set up or cure even when wet. It is available at most home centers under various brand names. I've used UGL's "Drylok Fast Plug," but there are many others. Clean any loose mortar out of the joint, and fill with the cement according to the directions on the can.
Because cement block is hollow, and water easily penetrates it, this method may not succeed. Since the fix is easy and inexpensive, however, you should try it early in the game. If, rather than an actual leak, the wall merely seems damp, a masonry waterproofing coating might work. There are many brands available. Consumer Reports reviewed these coatings in an article in February 1990 which is worth reading if you can find it.
Finally, could the ground be saturated with water due to a broken water line? There's an easy test. Shut off all water to the house for about 8 hours at your main shutoff in the house. Then check the reading at the water meter by the curb. Check it again when you return home. If it has changed by more than a half gallon to a gallon, you probably have a leak between the meter and your shutoff. It should be fixed as quickly as possible (another expensive project).
The remaining steps involve either back-breaking labor, or calling a contractor for help. Before the contractor proposes a very expensive solution, he should carefully diagnose the problem, confirming what you've discovered. While there are many possible fixes, the most common is to dig up the perimeter of the house, install a waterproof membrane on the outside of the wall, repair/replace/install drainage at the base of the foundation, and fill the trench with a good dense earth backfill over the gravel surrounding the drain.
While modern technology has come a long way in being able to waterproof a foundation, it often isn't required. Doing the simple things yourself may solve the problem. If any of you have had experiences with wet basements here in the Hills, I'd like to hear about them. In the next issue, I'll discuss finishing a basement.
It hardly seems fair that April will be bringing showers when we've had so many problems with water in basements in February. In this article, I'm going to repeat some of the material I wrote in 1992 on wet basements and add a new wrinkle or two.
The most common cause of water in the basement is surface water running down basement walls and into the basement through the concrete block or where the walls meet the floor. This is inevitably caused by gutter problems. Either the gutters are overflowing due to a lack of cleaning, or else the downspouts are dumping all the water from the roof too close to the house. Cleaning the gutters in late November and December after the leaves stop falling will solve the first problem (although they may need to be cleaned again before the spring rains start). Adding six to ten foot extensions to the end of the downspouts should solve the second.
A variant of this problem occurs when the ground near the house slopes toward, rather than away, from the foundation. Virginia Hills houses didn't get the world's most careful backfilling around the foundation in the 1950s, and the practices that were tolerated then would never pass muster today. As a result, the ground has sunk over time near the foundation. Adding fill near the foundation will restore the grade away from the house.
Never plant deep-rooted plants near the foundation. Roots offer pathways for surface water to make its way down to the base of the foundation and eventually into the basement.
One of the biggest causes of water in the basement is one that I haven't discussed before. If you have a stairwell down to a walkout basement, that serves as a big collecting basin for water. If the water level rises high enough, it will come in under the door and can really make a mess. The way water gets out of the stair well is through a drain at the bottom. The dirty little secret is that these drains need regular maintenance to function properly. If the drain gets clogged, you're going to have a serious water problem.
These stairwell drains can drain the water four different ways. First, they can drain to daylight, that is, they can run far enough away from the house so that they come out on the surface of a hillside. While this is the most desirable, it's the least common because the ground needs to slope down from the house eight to ten feet so the drain can get to daylight.
The second possibility is that the drain goes to a dry well from which the water can soak into the ground over time. This method is rarely seen because dry wells often clog with silt over time and then don't drain at all.
A third possibility is that the drain empties into the perimeter drain system of the house. The problem with this is that the perimeter drain can get clogged, and if it does, the problem is just compounded by the water from the stairwell drain. Also, the house may not have a perimeter drain.
Finally, the drain can empty into a hole called a sump with a sump pump to carry water up and away from the house. The problem with this system is that if the sump pump fails or is overwhelmed, you have no drain at all.
Some of the necessary maintenance is common to all these methods of draining. First, clean your gutters! If water is coming off the roof into the stair well, you're getting far more water than you normally would and more than the drain may be able to handle. Second, remove leaves and other debris out of the bottom of the stairwell on a regular basis. Leaves not only sit on top of the drain and block it, but also decay into earth and go down the drain, blocking it further down. If the bottom of your stairwell has become your own private compost heap, you're going to have problems. Third, at least once a year or so, you should put on some gloves, remove the cover from the drain, and reach down it to remove any dirt or other obstacles you find. A garden hose with high pressure can sometimes blast obstacles out of the drain. However, if water isn't going down the drain, you may need to call a drain cleaning service or use a plumber's snake.
Sump pumps must be correctly sized. An anemic pump will be overwhelmed by a lot of water. Again, using a garden hose to test your pump when it isn't raining is a good idea. You should also investigate having a battery backup on your sump pump. If you should lose power for a period of time, you'll end up with a lot of water in the basement.
A last ditch solution to the stairwell drain problem is enclosing the stairwell so that no water can possibly get in.
Copyright Doug Boulter, 2003
In my last two columns, I've discussed how to stop basement leaks. After you're sure your basement is bone dry, you can go about finishing it. A remodeled basement that doesn't look like a basement will go a long way toward increasing the value of your home and giving you space in which you can enjoyably spend time. In this column, I'll discuss how to finish your basement walls.
As you finish basement walls, you are looking for several things. You want walls to be attractive, to feel solid, to help keep you warm, to reduce the noise from the outside and other rooms, and to help give the basement a light and airy feeling. This is a tall order for a wall, but can easily be done right with a bit of effort.
First, walls should be attractive, suggesting a finish that is drywall, plaster, or paneling. Although no one builds walls of lathe and plaster anymore, plaster is applied over a type of drywall called "blue board." This is a project calling for skills beyond those of most of us, however, so I'll limit our alternatives to drywall and paneling.
Second, you want your walls to feel solid. Unfortunately, this pretty much rules out the 1/8" paneling that often is used to finish the basement, unless it is applied over drywall. Paneling over studs, no matter how nice it looks, will always have that hollow sound, and will not add much to the value of the house. A better alternative for the paneled appearance is to use 3/4" pine boards and stain or paint them to your taste. Standard 1/2" drywall will also give you a solid wall and will match the appearance of the rest of the house.
Reducing the noise from outside and from other rooms goes hand in hand with keeping you warm. The solution is to insulate the wall cavities with fiberglass batt insulation. By using the wall construction I'll discuss, you can get R-19 insulation in the outside walls. While insulating the interior walls won't help keep you warm, it will cut down on noise from other areas of the house.
Finally, the rooms should look light and airy, not like the typical dark basement. Here, the answer is to use light colors to finish: a light stain, a polyurethane, or a light colored paint.
Before we start to build walls, we need to make fixes that can't be done after the walls are up. If there are cracks in the mortar joints in the concrete blocks, these should be re-pointed (old mortar chiseled out and new mortar applied). A mason can do this, or you can do it yourself. Remove any nails in the concrete block and fill the holes. Next, if the wall is below the ground surface (below grade), it should be waterproofed with one of the several waterproofing paints or compounds. When we're done, the concrete block wall should have an unbroken surface. We won't be nailing into that wall, or fastening anything to it!
The final fix is to caulk above the concrete block where the wood ceiling joists sit on a wooden sill and run into a board called the band or rim joist. Construction in the 1950s didn't pay much attention to air leaks, and you may find lots of cold air coming in here in the winter. Caulk all around this space. If you do it on a cool fall morning, you can feel where the cold air is coming in.
If the wall we're building is below grade, we'll first install a vapor barrier of 4-6 mil thick poly sheeting. Use construction adhesive to secure the poly to the concrete block just at the point where the ground meets the wall on the outside. Then run the poly down to the floor, and let it cover the floor to about 6" out from the wall. Overlap and tape any seams in the poly sheets.
Use pressure treated 2x4 for the bottom plate of the wall. The rest of the wall can be made of regular pine/spruce 2x4, but should be good quality lumber, not twisted, cupped, or checked. Attach the studs to the bottom plate every 16" or 24" (this won't be a bearing wall, but 16" will make it feel a bit more solid). Frame around any windows. Add the board along the top (the top plate) at the appropriate height. Raise the wall into place, making sure you leave a 1" gap between the studs and the concrete block wall. Set the bottom plate on top of the poly you let lap over the floor so the wall is isolated from dampness. Nail the bottom plate to the floor using the powder actuated fasteners you shoot from a gun (which you can rent for a day). If the wall runs perpendicular to the ceiling joists, shim if necessary and nail to them. If the wall is parallel to the joists, you'll have to install pieces of 2x4 between the joists as nailing strips.
Now we're ready to finish the walls. In my next column, I'll talk about how to do that, how to soundproof walls, and, something we need to attend to prior to doing a ceiling--stopping floor squeaks.
Copyright Doug Boulter, 1992
I regularly visit realtors' open houses in Virginia Hills to give me ideas for this column. One trend I have noticed lately is an exaggeration of the number of bedrooms in a house. When I see the rooms that the realtor is counting as bedrooms, I know that some can't legally be bedrooms. When I ask the realtors about this, some express great surprise. In this column, I'm going to make you smarter than they are about what can be counted as a bedroom.
In Virginia, we are governed by the 1995 edition of the CABO One and Two Family Dwelling Code. In Section 310.2, it imposes an exit requirement for all sleeping rooms, the purpose of which is fire safety. The last thing you would want is to have a member of your family trapped in a bedroom with no way to get out. The section begins "Every sleeping room shall have at least one openable window or exterior door approved for emergency egress or rescue. The units must be operable from the inside to a full clear opening without the use of a key or tool. Where windows are provided as a means of egress or rescue they shall have a sill height of not more than 44 inches above the floor."
Since very few bedrooms have a door directly to the outside, a window will usually serve as the means of exiting the room in an emergency. The requirement of a 44" sill height, or the height from the floor to the bottom of the window, means that you may not have a bedroom in those areas of your basement that are mostly underground. In those Virginia Hills homes that have true walkout basements, there are windows with sill heights of about 40", so those could be exit windows.
The Code goes on, however, to say in section 310.2.1 that the window must have a net clear opening of 5.7 square feet. A clear opening means that area of a window that can be fully opened at one time. This will depend on the type of window. For example, if you have a window that is 2' x 3', if that window was a casement, the clear opening would be almost 6 square feet. If it was a double hung or slider window, on the other hand, the net clear opening would only be 3 square feet.
That section goes on to say that the minimum net clear opening height must be at least 22" and the width shall be at least 20". Since 5.7 square feet equals 821 square inches, you can see that if one of these two dimensions is the minimum, the other will have to be substantially greater than its minimum.
Let's take some examples. Our window that was 24" x 36" would give 864 square inches, and would meet code. If the window width of the opening was the minimum of 20", the height would have to be over 41". If the height of the opening was 22", the width would have to be 38" or more. Fortunately, most Virginia Hills homes with true walkout basements have at least two windows that will easily meet this requirement if casement windows are used. These windows are usually at least 31" x 43". There is an even bigger window that will work for sliders since half the space would be more than 21" x 43", giving an opening of at least 903 square inches when the slider is open.
Finally, the code offers an exception: "Grade floor windows may have a minimum net clear opening of 5 square feet." A grade floor window is one that is on the ground floor. You can step right out the window to the ground. This reduces the net clear opening requirement to 720 square inches for those windows.
The building code cannot influence what you do with a room in your own house. If you choose to have children, loved ones, or visitors sleep in a room from which the only exit is out the door, no one will visit your house to stop you. Imagine, however, that the person wakes up in the middle of the night with the smoke detector outside that bedroom going off. They feel the door and it is hot to the touch; smoke is seeping in under the door. They know they can't go out through the door, or even open it. The only window in the room is a small slider about 72" above the floor that is 26" x 14", giving a net clear opening of not much more than a square foot. Let's say that person managed to drag a night stand under the window and break out all the glass and frame and crawl out before they were overcome by smoke, badly cut but alive. Let's say that the story has a happy ending. Is this the risk you want to take?
I am concerned by the number of homes I see in which just such a room is offered up as a bedroom. This isn't fair to the buyer, to sellers of other homes, and to realtors who play by the rules. Nor to the innocent children who may put there to sleep.
Copyright Doug Boulter, 1998
Finally, our basement project is at the point where it's time to install our finished ceiling. There are several ways of finishing a ceiling, but we may be limited by how our lower level was built. Houses in Virginia Hills came in essentially two varieties. Where the house's "front door" came in on the bottom floor, the builders allowed well over 8' from the floor to the joists above in anticipation that the space would be used as living area. In such houses, almost any ceiling option is available. In other houses, where the bottom floor is really a basement, the distance between the floor and the joists is just a shade over 7'6". This is a problem because the building code specifies that "habitable rooms, except kitchens, shall have a ceiling height of not less than 7'6" for at least 50% of their required areas." As a result, our choices of ceiling are very limited.
By attaching drywall directly to the bottoms of the joists, we will have a finished ceiling that meets code requirements. While the joists in Virginia Hills houses are reasonably level on the bottoms, it's a good idea to check. Take a piece of 8' lumber that you know is straight and test along the joists, looking for light between the board and the joist. If you see light, the joist is either bowed up or down and might cause a noticeable bow in your ceiling. You can fix this by "sistering" (attaching) a straight piece of lumber to the side of the joist to support the drywall or using thin pieces of lumber on the bottom to lower the joist slightly where it's bowed.
Next, take your straight piece of lumber and try it perpendicular to your joists. Again, look for light under any joist. If you see light, you may have to sister a piece of lumber or shim to bring that joist down to the level of its fellow joists. Check with a level to insure that the board (and your new ceiling) will not tilt down at one end or the other. Test along the joists about every foot to make sure that there are no surprises anywhere in the ceiling.
A rule of thumb is that differences of 1/8" or less will not be visible and can be ignored. If that's all the light you see, or that's all the ceiling is out of level, you won't have to make any fixes. If the problem is more than 1/4", most people will be able to see the problem, especially when sunlight or light from a lamp below falls on it. Between 1/8" and 1/4" is pretty much your call. If that's the slope to the ceiling, let it go. If it's the bow to a joist, I'd try to fix it. Carpenters and your eagle-eyed friends will spot it.
The method of hanging a drywall ceiling if ceiling height were no problem would be to nail 1x3 pine strapping 16" on center perpendicular to the joists, using shims to insure that this strapping was perfectly level. Hanging the strapping is easier than shimming and sistering. The 3" (2 1/2" actual) width of the strapping also gives you a much wider nailing surface on which to butt the drywall, and you are also much less likely to miss when you screw the drywall into place.
This sounds simple until you look up and see all the electrical wire, copper pipe, and heating duct that runs BELOW your joist and would interfere with this ceiling. How can we deal with that? And what about water shutoff valves that we must have access to? The building code allows us 6" more that we can go down for the other 50% of the room. Also, for hallways, as an exception, the ceiling must be only 7' high. Therefore, as much as you can, run your plumbing, ducts, and wiring where the halls will be and install a lower ceiling. In the rooms themselves, box out your ducts by building a frame around them at the perimeters of the room. Keeping them on the perimeter will hide them visually, but may take some careful planning as to how you lay out the rooms.
You may have to have a plumber or electrician re-route some of the plumbing or wiring so that it goes through the joists rather than under them. This isn't very expensive and is easier than trying to reframe the ceiling for the sake of a few inches. If you must have access to what's under the ceiling, the bottom of your box can use suspended ceiling panels.
Next time we'll discuss other types of ceilings and more building code requirements for your basement.
In the last issue, we talked about putting drywall on the ceiling. This time, we'll talk about some alternatives you might prefer to drywall.
Some people like the appearance of a textured ceiling. One advantage is that you don't have to finish the drywall very carefully. You should still tape the seams and apply a coat or two of mud, but the texturing will cover this, so getting it exactly right isn't important. Texture paint can be applied with a special roller, and you'll get a nice textured effect. If you hired a pro to do the job, he or she would spray joint compound on the ceiling with a special gun that allows for control of the thickness of the texturing. The downside to texturing a ceiling (or a wall) is that you can never do anything else with it. If you decide that you don't like it, you will have to pull the drywall down and start over.
Some people like a more rustic ceiling. The easy way to get this is just to paint the joists and the underside of the sub floor. This means, however, that your wiring and plumbing can't be hidden, and you can't soundproof. An alternative is to hang drywall between the joists, leaving the bottoms of the joists exposed. This is a job that requires very meticulous work to get right. To hang the drywall, you must install strips of wood to which you can screw the drywall inside each joist cavity. Next, you must cut the drywall carefully to insure a good fit. Any gaps you leave between the drywall and the joist will need to be carefully filled with mud and sanded down. Before painting, protect the joist with masking tape if you want to retain the natural wood effect.
My favorite effect is to use wide pine tongue-in-groove planking which is nailed to the underside of the joists. You can buy this material in various widths and in lengths up to 16', so cutting is minimal. This planking is blind nailed to the joists, nailing through the tongue of each plank at an angle using finishing nails. When this is done, no nails show except on the first and last boards which must be face nailed. This is the same way a floor is installed. I prefer to finish the planking with a polyurethane sealer so the natural wood shows through, but the wood can also be stained to the color of your choice. The downside of this approach is the expense. The planking is not cheap, but you get a nice effect.
Many people like a suspended ceiling because it allows them access to the ductwork, electrical, and plumbing running in the joist cavities. A suspended ceiling will reduce your headroom by about 3", but if you can spare the space and are willing to pay for a quality product, you can obtain a very nice appearance. Here's an outline of how it should be installed. Read the instructions that come with the materials very carefully. This is more complex than it looks.
First, snap a chalk line on each of the room's walls 3/4" above where you want the ceiling. This line will mark the top of the wall molding. It is critical that all your chalk lines are level. Use either a very long carpenter's level or a water level. Second, hang your L-shaped wall molding, making sure you have at least 3" between the molding and the joists, so you can get the panels in.
Next you must plan the ceiling tile layout very carefully on paper. Unless your room is an exact multiple of 48", you will end up cutting the outer row of tiles on each of the walls to get the proper look. Mark the location of each metal runner (the long dimension) on the wall. Stretch a reference string tight between the two walls. To hang the runners, cut them to size and rest them on the pieces of wall molding just beside your string. Every 4', loop a hanger wire through the hole of the runner and attach it to the joist above, but do not fasten it tightly. Use the string to get the runners level. Once all runners are installed, check with another piece of string across the runners to insure they are all the same height. Twist the wire to raise or lower the runner.
Once the runners are up, install the cross tees. Remember that you will probably have to cut the two outer rows to fit since the tiles will be smaller. Once the cross tees are installed, you can install the ceiling panels. Use care when handling the panels so as not to damage the edges.
Next time we'll conclude by talking about some general building code provisions that apply to basements and how the electrical should be done.
Copyright Doug Boulter, 1993