I am going to be putting interior nonload-bearing walls around the side of the basement block walls and have the come across the following two concerns.
1) I have heard from different sources that the block wall does/does not need a coat of sealant. Those saying ‘aye’ have said that the wall anchors will crack the block and mortar allowing water to seep in over time, thus the need for sealant. The ‘nays’ say that the coating on the exterior will take care of the water and to seal the inside is a waste of time, materials and money. Who is correct please?
2) In one corner, the untrimmed edge of the window is only 3 inches from the corner, not leaving a lot of room to fit the hold-off strip, studs and drywall, let alone window trim. The wall next to the corner is 19′ long so any suggestions on how to build the wall so that it is even throughout the length would be greatfully received.
I am going to use metal framing for the other walls, but can mix materials if that is the answer.
Scooter
Replies
Use 1 5/8" metal studs secured to the slab and structure above, with standoffs at mid-height secured to the stud, but not to the wall. That'll solve the problem of the anchors into the wall (since there won't be any), and also accomodate the 3" dimension to the window.
Bob
As for coat or no coat, I'm in the process of applying Tamoseal, a portland cement-based concrete waterproofing, to the interior side of the bare block basement wall in the utility room.
About half-way there applying half-bag mixes each time whenever I get a chance.
After addressing some questionable gutter drain arrangements when we bought the house, the basement wall has dried out and humidity level sufficiently normal during the course of a year to go ahead and apply the coating.
Even if there isn't a moisture problem, I think it's a good idea to apply some sort of coating to bare block or concrete basement walls before erecting any finish walls.
But that's for our situation - others may vary.
Check the basement finish details at http://www.buildingscience.com. I'd guess you're right to Thoroseal the walls if that's all the finish you'll ever do, but Dr. Joe et al says no impermeable wall coating or membrane on the inside of a basement wall that's getting a finished wall as well. FWIW, until I read that recently, you and I would have said the same thing.Arguing with a Breaktimer is like mud-wrestling a pig -- Sooner or later you find out the pig loves it.
Yikes, I spent a lot of time downloading and reading most of the material from Building Science but maybe I got a little bug-eyed with information overload.
I'll look for his article or maybe I already have it and missed.
The utility room probably will not be finished beyond what I'm doing.
This is not a complete 'basement' per se, but with two hopper windows and the rim joist is just shy of daylight.
Took me several years of waiting to make sure the block walls were ready for a good quality coating, which was narrowed down to ThoroSeal or TamoSeal.
Thanks for the heads-up.
Edited 2/26/2004 4:46:52 PM ET by Ahneedhelp
Yeah, there is a lot there. The bottom line is that basement walls can only dry by vapor diffusion, and you have to allow them to do that or you will have water issues somewhere. Unless you live in the desert, they can only dry at the outside above grade area, or to the inside. That works great in the winter when the moisture drive is outward, but not in the summer when the moisture drive is inward. The trick in the summer is that if you live where it's humid, then any air that hits the cool wall is likely to condense and worsen the problem. That's why he recommends semi-permeable foam insulation applied directly to the masonry. It allows vapor diffusion inward while preventing moisture laden air from contacting the wall and condensing. Fascinating stuff.Arguing with a Breaktimer is like mud-wrestling a pig -- Sooner or later you find out the pig loves it.
Thanks, Andy -
You recapped the stuff that I read and it's a good summary.
I didn't think through the need for the wall to be given to chance to dry through diffusion.
Since the very porus cinder block walls have been dry for several years and I think the rise in humidity level in the basement has been moderate during the summer, I feel ok with what I already started.
I think most of the added humidity has been entering through the original hopper windows and steel casements in the basement.
And it rises also when we open the main floor windows and the humidity drops down into the basement.
We run a dehumidifier that drains to the floordrain.
There are two walls, 12' and 33', that I'm parging over.
The white does drastically change the appearane of the laundry/boiler/workshop area.
Thanks for your messages.