How to Finish a Basement (flooring, dehumidifier, foundation, heat)
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Looking for help with finishing a basement. The walls are block. Location is SW Pennsylvania. Want to frame it an put up dry wall. Looking for tips.
Steps in order
1. Paint using dry lock paint.
2. Was thinking foam board attached to the block wall
3. After leaving an inch or so putting up the framing, using pressure treated wood for the bottom plate
4. insulation???? Not sure what kind. Faced or unfaced? Which side to put the paper?
5. Vapor Barrier?
Does this sound right? My father had his finished and his contractor omitted the foam board.
What I did in my house that had constant water issues in the basement was make sure that the perimeter gutters were in good shape, then cover the wall and about a foot of the floor with six-mil builders plastic, then left about an inch and used 2 x 3's for framing it out, R-8 insulation and removed the insulation facing at about the 6' level. Then covered w/ 3/8 sheetrock. Why?
The builder plastic is a positive vapor barrier, unlike drylock, which can weep. Running it under the sill plate also helps moisture issues there. Moisture condenses less on the wall because of the insulation. Any moisture trapped between the insulation and vapor barrier will release with heat as the moisture rises and comes to the section where the insulation is unfaced.
When finishing a basement - resist the temptation to carpet. Use washable rugs that can be removed for cleaning.
The "gold standard" for basements is ALWAYS to start with as dry a basement as possible. You want to keep any seepage from EVER getting into the space. If you have any doubts that water will work its way into then you ought to provide for interior perimeter drains. There are several options for doing so, many are awfully pricey, some just so messy / space hogging as to be impractical...
Leaving aside thhe issue of seepage the question of how to frame and insulate is somewhat easier to deal with. The top notch solution is generally to use not pressure treated wood, which is designed primarily to resist insects, but with "moisture resistant" lumber that has been treated wtth a bright blue coating "infusion film". It works well at preventing mold and is much faster / cheaper / more reliable than trying to PRIME all the framing with something like PERMA-WHITE/PERMA-GUARD which is also excellent.
Steel 2x4s tend to transfer too much cold back through the drywall and that leads to excessive condensation and eventually mold. Insulated steel 2x4s are available but they do not work well enough to justify their cost IMNSHO...
Next goes up the rigid insulation. I personally prefer the higher R value inch and slightly better physical characteristic of ISO (polyisocynaurate) over XPS (extruded polystyrene) but XPS is often cheaper. I would NEVER use and type of batt insulation in a basement -- potential for wicking is just not worth the risk.
After the insulation is up the generally accepted standard is to use a reinforced solid sheet impermeable true moisture barrier with appropriate tape at all seams. The idea is that you are going to seal anything (including radon or other gases that might escape from / through the foundation) into the foundation space and out of the living space.
The last step highlights why you need to either plan for interior drainage OR be darned sure you won't be getting any seepage. That vapor barrier is designed NOT to breath. Any moisture will disapate VERY slowly. Which is great for the comfort / cleanliness / safety of basement and furnishings. Not good it the stuff back in the foundation space is not mold resistant...
CMU's are notorious for leaking from several different fronts. Mainly, during the wide spread use of CMU's "waterproofing" was a misnomer. Most were only "damp-proofed"- a mere light coating of asphalt tar. Good for about 5yrs.
If you're following along- the only effective way to stop moisture penetration with a CMU foundation is on the exterior. Even if you used the "best product" on the market for the interior side of the walls- what's to keep the core portion of the wall from filling with water? You can still have a hydrostatic pressure failure and a few less obvious type failures that are for another thread.
Anyway, moving right along- Foam board/XPS (Dow blue board or OC pink) is a great insulator and vapor barrier. As long as it is installed correctly and sealed. Since it is also a vapor barrier you can frame pretty much right against it.
As far as the insulation-
http://www.eere.energy.gov/buildings/building_america/pdfs/db/35017.pdf (broken link)
This is probably the best information I've run across- I've had this pdf on my computer for quite awhile. Unfortunately, it's too big to upload on C-D.
I would also strongly recommend (because of the existing conditions) that you use paperless d/wall.
Not necessary. A waste of money. Paint will not keep water out if your basement is sitting in water. You should have a good drainage system and sump pump. If your system fails, you are going to have a water intrusion problem and no paint tar or other goo is going to prevent it. You cannot waterproof our basement. You can make it more water resistant, but that is mostly effective when done form the outside. Water resistance does very little. If it is sitting in water, the water will come in. The only way to avoid that is to get the water away from the basement. Think of your basement as a boat. Take it out of the water, and it will stay dry. Put it in water and no 1/1000th of an inch layer of paint will keep the water out, no mater how expensive the paint is or how many representations the paint can or salesman may make to you. Either, you get the water away and do not have a problem, or you have water there and you have a problem. Paint will not change that.
Water resistance or damp proofing is often a waste of time and money. If the drainage system works, it is not necessary. If the drainage system does not work, it will not change the end result. Damp proofing can be useful if for some reason you have an unusually porous basement amd lots of water and you need to hold the water back until it is drained away by your drainage system.
If your drainage system is inadequate, do not finish your basement. You will not be able to keep the water out. Spend the money on putting in a drainage system. Sometimes a drainage system fails to keep the water out. That is really rare. Usually is it due to a problem whit the grading in your property, could be a re-routed underground stream, could be a change in a neighboring property. If your drainage system is being overwhelmed, you need to fix the problem. Paint will not help.
2. Was thinking foam board attached to the block wall
Why? If you are framing, you should be putting in insulation. Since your basement is not subject to extreme cold or wind, cheap fiberglass batt should be fine. If you are using those fancy foam boards from 3m then you do not use framing.
3. After leaving an inch or so putting up the framing, using pressure treated wood for the bottom plate
This is a good idea. Depending on the height of your walls you may want ot use double bottom plates. You do not really need to leave an inch or so. I am not sure that this will pass inspection structurally. Your base plate really should be in full contact.
4. insulation???? Not sure what kind. Faced or unfaced? Which side to put the paper?
Foil side faces in. If I am doing it myself, I like the totally encased fiberglass so I do not get it on me. Plastic is better than paper becuase paper will mold if it gets wet or damp.
THe bast option is ICYNENE foam. If ou insulate with ICYNENE, you will have to turn the heat down lots. But it is expensive.
5. Vapor Barrier?
Yes. This is a good idea. just staple some visquene to the back side of the walls when you frame them. It is not really necessary, but if your draining system slightly fails, then it could help keep moisture out of the fibeglass and more importantly, out of the paper backing until you fix the problem. If you have ongoing moisture intrusion then vapor barrier is not going to help long term. Hopefully your moisture barrier will be a waste of time, but in the event of a failure or other incident, it can help minimize damage until you solve the problem.
Basements do not need as much insulation as regular walls. You basement will stay right around 50 - 60 degrees. No amount of insulation will change this, you are underground. The ambient temperature will remain the same until you do something to warm the basement space. What the insulation does is to keep the heat that you generate inside the basement instead of being absorbed into the ground. Keep in mind that most of that heat is going to go up, not sideways.
Floors can be a problem since cool temps will transfer from the ground to the concrete and you will get cold feet even if the basement is warm. You can frame in a floor using treated 2x4s turned sideways and installed an inch or so about the concrete, or buy those little flakeboard squares with plastic feet that give you an air pocket. This also will allow a little bit of water to run below the flooring wihtout damage if you have a washing machine toilet or sump pump failure and flooding. Keep in mind that flakeboard swells and comes apart if it gets wet. I wish those things were made of plywood, but they are not.
If I were to do it again, I would terminate the drywall about an inch or two above the floor and use plastic moldings. That way if there is a flood of 1-2 inches, you only have to replace the flooring, not the walls and moldings.
Trying to set up your basement to deal with water problems is a good idea in case of an unusual event, but the basement must stay dry. You cannot have regular water intrusion in a finished basement. You will gt mold. You have to keep the water out. However once in a while something will likely happen that will cause a flood. For us: Sump pump was turned off by a worker; toilet installed incorrectly caused a flood; washing mahine hose broke; water pipe connection when something was leaned against it; unexplained sudden ground water intrusion (still seeking the cause, probably related to grading, possibly an underground stream). Except for events caused by interior water, our basement was bone dry for years. Suddenly we have a little stream flowing through one bedroom. No one has been able to come up with a reason for this. We have had unusually bad luck, but everyone we know had has water in their basement one way or another. Often it is caused by water from inside the house, not from outside. Basement bathrooms, or even upstairs bathrooms (leaving the tub running, shower curtain not inside the tub, etc). It is good to be able to deal with such event with minimum damage, but you will have to tear up the floor to dry the water out before it causes mold most of the time. If your carpet gets wet, just take it out and replace it. Drying it out costs more than replacement.
If you get flooding of more than the airspace below your floor, and someday you probably will, you will have to take out the floor and dry it. Usually it is cheaper to replace it.
We used fiberglass batt. Our walls and floor breathe. With minor water incidents, we can just let it dry out. However we had some really big issues. If you get a foot of water, you have a mess regardless of what you do. Given the likelihood that something like this will eventually happen, I woudl focus on keeping it simple and cheap to replace the lower portions rather than keeping tiny amounts of moisture out. It will get in. There is no keeping dampness out of a basement. A lot of the moisture, comes from inside the living space.
We did not get wicking and when the insulation got wet, we just cut out the lower portion and replaced it. We have no significant levels of radon. If we had a radon problem, I would not try to solve it with tape. This is another area where you want to take the problem away rather than attempting the impossible task of keeping it out.
Spend a couple of thousand for a really good dehumidifier. It will still be humid down there. It always is.
The cost is pretty steep. It cost us about $65,000 to finish 2/3 of our basement and we did a lot of the work ourselves. However, we had some bad luck including a 2 + foot deep flood that forced us to tear almost everything out and start over. ($5000 deductible plus other non-covered costs are part of the $65,000 total). If I did it over, I would focus on reducing replacement costs more than trying to keep moisture out.
Last edited by Coldjensens; 10-07-2011 at 09:12 AM..
Just food for thought. In one of my houses it had block walls. I painted them white. We added in a modern drop ceiling and the texture of the block walls actually added character. We installed some nice flooring. The end result had a loft kind of vibe. I got a lot of compliments on our "finished" basement. The drawback is that our basement could get pretty chilly during the really cold winter months.
If you want to finish the basement, or make an en exit to outside, and do it yourself, do you need permit from the city?
In most jurisdictions you only need a permit if you make a structural change, connect plumbing or electrical devices or intend to use the improved area for a bedroom. Electricians universally disregard the permit requirement for lighting and electrical outlets. So it comes down to whether the improved area is getting a new bath room.
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