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Question for those who used rigid foam to insulate a basement


whatshisname's Avatar
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03-25-06, 02:04 PM   #1  
Question for those who used rigid foam to insulate a basement

Question for those who used rigid foam to insulate a basement


I plan to insulate the poured concrete walls in my basement with rigid XPS foam. If you have used this method, what did you use for adhesive? How long did it take to set-up and hold the panels in place? What did you use to hold them until the adhesive set-up?

I wont be able to friction fit them top and bottom as there is a 1ft high knee wall (dont know what else to call it) at the top of my poured wall before the 1st level floor joists to give the basement an extra foot of depth. I will have to insulate that area differently so the panels will only go to the top of the concrete.

 
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whatshisname's Avatar
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03-30-06, 05:30 AM   #2  
Anyone..... ?

 
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03-30-06, 05:02 PM   #3  
Question for those who used rigid foam to insulate a basement

One of the classic reasons people use block for a higher ceiling - it is not limited by the average concrete form heights.

Use an adhesive that is compatible with your EXTRUDED polystyrene, not EXPANDED polystyrene. The are many adhesive brands -just look at the labels for instructions.

Usually, you can get the best results, by applying the adhesive, pushing it to the wall, pulling away, waiting a perscribed period of time and then pushing it back to the wall. If you choose, you can brace with a diagonal 2x.

You are not holding anything up, but just keeping the adhesive in contact with the wall until it has adhesion and pulld itself to the wall.

For the top one foot - use scrap insulation to fill the gap and run the insulation from floor to ceiling (horizontal or vertical sheets) and cut pieces for gaps. You do not have to worry about air infiltration in a basement when surface bonding materials.

If you need nailers, just glue in before putting up the insulation.

Dick

 
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03-31-06, 11:46 AM   #4  
Thanks for replying Dick. Yes I was planning to use EXTRUDED, took me a bit before I found the difference.

I was planning to fill that top foot with loose un-faced batt type insulation as you suggested. But are you saying to run the foam all the way up to the ceiling over that. I was planning to stop at the top of the concrete (8ft, same as the panels). If I go all the way up with the foam I will end up cutting all the panels to add that foot (I guess sort of like staggering drywall or tile). Would it be OK to stop at the top of the concrete or do I NEED to go all the way up? Thanks for the help.

Oh also, whats the cleanest way to cut this stuff? Can you score it and snap it sort of like drywall, or do you have to cut it all the way through with something?

Also curious as to how much adhesive I will need. I need to put up 35-40 4x8 sheets.

Thanks

 
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04-07-06, 04:37 PM   #5  
I have another question.

I purchased STYROFOAM Residential Sheathing extruded polystyrene insulation. The foam insulation board has a thin plastic film on both sides. No-one had the plain STYROFOAM Tongue and Groove extruded polystyrene without the plastic film on both sides. The sales people at all the stores said it was the same stuff other than the plastic film. the DOW website says the plastic film reduces job site damage to the insulation boards.

My question is, do I remove the plastic film on both sides or at least the side that I am gluing to the concrete walls? It is already slightly peeling on the edges and I cant imagine the adhesive will hold the best.

 
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06-01-06, 10:51 AM   #6  
How to seal the seams?

I have another question to add since I'm doing the same thing, or maybe you've already finished and know the answer, whatshisname. What do I use to seal the seams between the sheets of extruded foam? I did find the tongue and groove sheets although I could only find ones that were 2 feet wide. I tried normal duct tape on one of the seams and the next day it was already falling down. I read various things about something called mastic or mastic tape. Are they two separate things, and is that what I should be using? Thanks for any input.

 
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06-01-06, 04:25 PM   #7  
Use foil tape. You should find it displayed near the duct tape. Home Depot and Low's carries it.

 
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06-02-06, 06:04 AM   #8  
Thanks, rjordan.

 
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