I’m a homeowner undergoing a remodel that includes building out a space below our living room. We had to dig out about 2 feet to get 9 foot ceilings and I’m happy to say no one would ever think it was a former garage.
My concern is that along the bathroom exterior wall, part of which is about a 2 or 3 below grade. There is a combination of cement block wall and framing (PT where in contact with block). They used PT 2x4s to make a near 2 inch space along the block wall, and fit some foam insulation board between studs along that wall. Icynene insulation is sprayed in the frame part of the wall–which is really thick due to matching up with the block wall.
The block wall was waterproofed with a spray membrane. However, due to gaps in the mortar between a few blocks, rain has gotten into this shower area. The exterior is going to get a french drain and an underground pipe for the gutter downspouts, but that hasn’t been done yet and gutters aren’t in yet….so I know conditions aren’t normal yet. Given how porous cement is and how thin the insulation board is at the block, will this be enough to protect & inulate the walls–especially in the shower part of the bath which shares this outside wall? Is there a condensation problem wating to happen. I’m asking them to hold off doing the shower until I’m confident it’s being done right. I’d hate to put in tile and find I’ve got water problems building up behind it. Any thoughs would be helpful..there is a lot of wisdom out there!
Replies
Greetings EAL, 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
'Nemo me impune lacesset'
No one will provoke me with impunity
I'm not sure I understand all of the details, but it sounds to me like right now you want to address the waterproofing on the outside of the block wall below grade.
Did I guess correctly?
If so, then spray-on membrane is not enough.
Don't connect the gutter downspout to the footing drain. They should remain seperate, with the gutters led away from the house.
For waterproofing the outside wall there are several commercial variations of the same strategy. These involve sheet membranes about 40 to 60 mil thick and a dimpled plastic sheet with a fabric that provides protection for the membrane and positive drainage.
http://www.nahbrc.org/tertiaryR.asp?TrackID=&DocumentID=2063&CategoryID=1022
If that is not an appealing option for some reason, the STO company makes a parging called Flexyl. It was developed for just such a use. It is bomb-proof.
In any case, if you do not solve the problem outside the wall, it will be difficult to solve the problem inside the wall.
Success is not the key to happiness. Happiness is the key to success.
-Albert Schweitzer, philosopher, physician, musician, Nobel laureate
(1875-1965)
Thank you so much! You seemed to understand exactly the issues. And the drainage mat sounds exactly like what I've been trying to tell my contractor for months! The link looks to be very helpful and I'll look forward to digging a little further--one panel design provides some insulation to protect against condensation, too. It certainly confirms that his idea that a 6 mil sheet along wall and wrapped around the french drain was a bad idea! With this info, I think I can keep us on the right track. Thanks again!
You are most welcome.Pretty much all I do for a living is dig holes and fill them back in. I'm often called to look at failed waterproofing and I always feel sad for the homeowners. It is so incredibly much more expensive to do it right the second time. It is also inexcusable for a contractor to do a bad job the first time.Good luck. Give us a yell here if you need more help.Sometimes I wonder whether the world is being run by smart people who are putting us on or by imbeciles who really mean it. -- Mark Twain, author and humorist (1835-1910)
Thanks for being out there---and for willing to share your wisdom! By and large my general contractor has been pretty good but for some reason, they weren't watching their sub on this...but they are stepping up to the plate now. Thanks again!
You're welcome. Glad I could help.Power always thinks it has a great soul and vast views beyond the
comprehension of the weak; and that it is doing God's service when it is
violating all his laws. -John Adams, 2nd US president (1735-1826)