Hello everyone. I’m new to this particular forum, but I’m hoping you can help me answer some questions I have about finishing my basement.
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I plan on finishing my basement using the techniques outlined in Andy Engel’s article “The Stay Dry, No Mold, Finished Basementâ€.
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First a little background on my basement:
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We moved into our house (40 year old Colonial) about 6 months ago. I’m still in the process of improving the grading and gutters to keep as much water away from the house as possible. From what I can tell, it looks like our home has an interior French drain. The slab sits about 1.5 inches out away from the wall, and that space is filled with gravel. The block wall has ½â€ weep hole spaced about 12â€-18†OC around the perimeter of the basement that are about level with the slab. And there is a floor drain that the slab slopes towards. We have a dehumidifier that runs pretty often in the summer. The only time we have seen any kind of water in the basement is when it rains very hard (2â€/hr) for a couple hours (which it did last year). We get a trickle of water that comes out of the weep holes and into the drain, but never any accumulation.
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Now, for the questions:
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1) If I install the 2†rigid insulation against the wall, will the water (if we get any) just run off the insulation into the interior drain? Should I be worried about mold growth along the base of the slab? If so, anything I could do to prevent mold growth?
2) The finished floor will not cover the existing floor drain. But since the floor slopes towards the drain, I may need to shim the floor insulation to make the new area level (or pretty close)…any ideas?
3) Any possibility of water coming up through the floor through the holes made by the tapcon screws?
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Sorry I was so long winded. Just want to make sure I do this right the first time!
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Thanks!
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Trev
Replies
Greetings Trev,
As a first time poster Welcome to Breaktime.
This post, in response to your question, will bump the thread through the 'recent discussion' listing again.
Perhaps it will catch someones attention that can help you with advice.
Cheers
sobriety is the root cause of dementia.
now, how exactly do you bump a post?
Greetings mrhodes,
now, how exactly do you bump a post?
I don't know if that is a serious question or humor since I so frequently post those statements you are referencing.
Cheers
sobriety is the root cause of dementia.
I use a hydralic accessory ram on a Bobcat.But you hve to be very carefull that you only bump it and not knock it over.
View Image
sobriety is the root cause of dementia.
Will the 2" insulation be glued to the inside of the walls? If you fit it tight against the wall, the moisture may not have any space to drain. If you use furring strips to creatre a gap between the foam and the wall, the moisture will fall to the floor. Just don't seal the foam to the floor ... leave a gap there too.
So you're going to foam the floor too? Why not lay down sleepers and raise the floor a couple of inches. 1-1/2" sleepers + 3/4" advantec only costs you a little more than 2".
If you drill the tapcon holes deep enough to go all the way through the slab, then you have a place for water to get in. Don't drill so deep.
Or don't even use tapcons. Glue the sleepers to the slab with PL or similar adhesive.
I'm sorry, I thought you wanted it done the right way.
Thanks for the response.
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If I remember the article correctly, it called for 1” rigid insulation on the slab, with ½” plywood over the foam, screwed into the slab with the tapcon’s, then another layer of ½” plywood on top of that, running in the opposite direction of the first layer.
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I don’t have very high ceilings in the basement, so I’d prefer to keep the floor “build up” as small as possible.
Would gluing the foam to the slab with a liquid nails (or appropriate adhesive) be adequate? Could the first layer of plywood also be applied to the foam with the same method?
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Would I be better off skipping the 1” foam and instead gluing 1” sleepers down and attaching the plywood to the sleepers?
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Thanks.
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Trev
If you don't have that issue, you can buy the back issue at taunton or check it out from your local library, it was issue 169, sliding door article on the cover.
For some more basement info, check out these http://www.buildingscience.com/resources/foundations/basement_insulation_systems.pdf
http://www.buildingscience.com/resources/mold/Read_This_Before_You_Design_Build_or_Renovate.pdf
Also, do a search in the archives of this forum, I remember the writer of the article, andy engel, had a bunch of different things to say after that issue came out.
Also, for the floor you might want to look at http://www.dricore.com. They might be a better option and save you both labor and head room. I think they are about $4 for the 2'x2' squares.
Here's at least one of the threads that was started about the no mold basement article. 53000.1
If you're worried about ceiling space another alternative for your floor is a product called Delta-Fl (I'm in the process of a basement project as well and this is my plan) http://www.deltams.com/deltafl/index.html this would seem ideal for you as it provides similar protection to what the FHB article suggests. It is also designed to have a gap around the edge so any water can collect in your perimeter drain. You can supposedly place a plywood T&G subfloor over it if you want to carpet or use engineered floring directy on top of it (after the flooring laminte foam). There are a few old threads on it here of people who seem to like it.To be honest I haven't seen the article (wish I had, but I just subscribed to the magazine) but I've read the building science articles and this looks like it might be a great alternative for you. Tom
Thanks for the links and the info!
Trev, the drain detail and the occasional presence of water concerns me. Although it sounds as if the exterior improvements you made are going in the right direction, I'd be reluctant to finish that basement until it had weathered at least one major storm with no liquid water entering. Liquid water is nasty stuff, and hard to dry.
Assuming no water entry, here's a way to detail the wall around the drain. I'd nail or Tapcon a pressure treated ledger to the wall above the weep holes. Cut some 2 in. foam to the same height, and glue it to the floor beyond the gravel drain. Liquid Nails or spray foam will work. Bridge between this foam and the ledger with more foam, then cover the remainder of the wall with 2 in. foam as in my article. This cavity you've created should at least keep capillary action to a minimum, and allow some drainage should your improvements to the outside eventually fail. I'd also find some way to add inspection ports. The stud wall should go to the outside of the foam.
You can use the DeltaFL panels. I don't because they offer little insulation, and create a vapor barrier. The idea is to allow drying to a dehumidified interior, and vapor barriers prevent this. On the floor, these may be small concerns.
Andy
Andy Engel
Senior editor, Fine Woodworking magazine
Other people can talk about how to expand the destiny of mankind. I just want to talk about how to fix a motorcycle. I think that what I have to say has more lasting value. --Robert M. Pirsig