finishing a basement that had water issues

[gleinb]

Hello!

this is my first post.... we want to finish our basement and it had water issues in the past but the previous owner installed an inside water removal system that shunts water to the sump pump and then out. you can see where the water came in in the past but so far (fingers crossed) after a year here we haven't seen any new water issues on the walls.

the question is: can I put up polystyrene insulation without worrying about moisture collecting behind it and starting to collect mold? i don't want to finish the whole thing and then have to rip it all down (which is what they had to do). can i (should i) install some sort of plastic sheet that funnels water down to the channel around the outside of the interior walls?

thank you for any help you all can give!!!

 

[nealtw]

Welcome to the site, can you post some photos of the work that has been done?

 

[gleinb]

nealtw: here are two pictures, and then a cross-section of what i THINK it looks like underneath....

thanks!

 

[nealtw]

There are a bunch of right answers. So I will give a some things to think about.
Water will wick thru concrete from cold to warm, that is why they like to have 8" of foundation exposed on the outside so moisture can dissipate.
An un-insulated basement with heat can help moisture wick to the inside.
When installing this drain they should have drilled hole in the bottom blocks below the floor level to help water run down and out into the drain.
Drilling holes does not help if the block was filled with concrete.
We often see dimple board up the wall to above ground level or right to the top, I will post a photo of that and your poly sheeting would likely do the same job.
Up here we build a 2x4 stud wall 1" away from the concrete complete with insulation, vapor barrier and fire stopping.
One reason for doing the 2x4 wall is the inside of a concrete wall is seldom straight and that's to do with the forms we use for that.
I would think if you use foam, you could use one with ridges or puck shapes on the side that goes to the wall to allow water to run down. I would also install some kind of flashing cut into the bottom of the foam that would direct any water behind the dimple board.

 

[gleinb]

Nealtw:

Would I attach the vapor barrier directly to the wall? And if so, I don't have to paint the wall with waterproof paint, right?

Finally, I'd have the vapor barrier, then an inch of dead space, then the insulation (then ANOTHER vapor barrier, maybe? necessary?) and then the drywall, right?

THANKS!
G

 

[nealtw]

If water wants to come out of that wall there isn't much you can do to stop it from the inside with out spending lots of money. If you think about water coming thru the wall would be under pressure allowing the water thru might protect the structure of the wall.
The rule is one vapor barrier. any moisture in wood structure should be able to vent either inside or out. So a sealed poly against the wall would be the only one you need.
So you would seal the poly to the top, wood sill sitting on the wall and tuck it into the dimple board and tape it there with red (tuck tape). We seal it to wood with acoustic sealer, doesn't seam to be available in the states so I don't know what they use.
I will see if I can dig up an old post where the construction of the wall is detailed.