Tar on Interior Walls

Wondering if you all could help ease my worried mind.
My husband and I are currently building a house, small bungalow with walk out basement. This week we had the foundation walls poured. It’s really only one full wall in the front, the sides are half walls that are stepped down in the back and no back wall as it is a walk out basement and will be framed in.
My husband, who in his defense has been very stressed lately, got some bad advise from an uncle who told him he should have the bottom 4 feet of foundation tarred to prevent dampness. Something he did when he had damp/mold issues in his own house and it corrected the matter.
My husband had this done without speaking to me about it…so you can imagine how this went over when I arrived home from work yesterday.
The men doing our foundation didn’t seem to blink an eye when he inquired about it. So I’m hoping there will be no negative effects on the house or healthwise for us? When he told the contractor about this late yesterday, he looked at him like he was nuts and said you never tar the inside.
So, we are both now worried and panicked that this was a terrible mistake. I’m hoping someone out there will say, it was just a waste of time and money but won’t negatively effect the house or us?

Who told who what and did someone tar the inside?

Yes, the people who installed the foundation applied tar to the interior walls. The lower 4 ft on the front and probably 3 feet from the bottom on the side walls.

I have been in this business since 1972 and I thought that I had seen and that I had heard everything! For the first time in my life I am absolutely “speechless”:shock:

No way tar should be at interior.
Sounds like a court suit.

Tar is used to seal the exterior wall to help prevent moisture intrusion. The men building the foundation should know this, in fact sealing the exterior side of wall should have already been part of the building design.

Sealing interior side will not allow the wall to breath. Before you proceed further I would have an independent Qualified foundation contractor evaluate and see if wall is still salvageable.

The fact they applied tar at interior side shows they don’t have a clue. You need to hire a different building contactor. I’d hate to imagine what else they might do.

Waterproofing or damp proofing will only work when a coating of either tar or rubber is applied to the exterior foundation walls. Overtime, The only thing that keeps the coating on the outer walls is the soil pressure pushing on the outer wall surface. When a coatings such as dry lock paint or tar is applied to the inter walls it will push off and be ineffective. The contractor may be trying to cover up the fact that someone forgot to seal the outer walls which should have been caught by the local code official. I would have someone dig down at the exterior walls to show you that it was done. I agree with the others here that this shows signs of questionable workmanship. I would suggest that you hire an InterNACHI Certified inspector to be your eyes for the rest of the project. Check out this link to find someone near you. http://www.inspectorseek.comhttp://www.inspectorseek.com

I can’t give legal advise but I would talk to a lawyer for sure. Google health effects of tar and asphalt, there are different types and I don’t know what was used. As others have said it is just plain wrong and yes it was a waste of money and time. You should probably hire someone (as John said) to over see the rest of the project it may very well save you money in the long run from costly repairs and headaches.

I’m with Frank on this. I’ve been in the business since 1973, and have never even heard of anything so stupid. You need a new contractor. The current contractor is obviously incompetent. You’re not acting as your own General, are you? Big mistake if you are. You’re only at the foundation. There are alot more mistakes that can be made from here.

What about closed cell foam?

Thank you for your comments. No, we are not acting as our own contractors. The contractor wasn’t at the house when this was done and wasn’t happy when he found out.
It happened because of a stupid conversation between my husband and the people doing the foundation. And a lot of miscommunication apparently.
I’m just not sure why they did it. These people supposed to be the best in our area and have been around for a long time.

We have scraped most of it off now, luckily it’s not going to be a large house because it’s a lot of work. There is still a very thin layer, but hopefully by the time the house is sealed in the smell will have dissipated. And we plan on finishing the basement so with vapour barrier, insulation, foam and gyprock I’m praying it will hide any remaining scent.

I started comstruction in the early 70’s, built many homes with poured and block foundations and was a form carpenter in the 70’s and never saw tar on an interior wall.


I would be more concerned with the health aspects than anything.

What product was used would be informational for any health issues.

Here is a good link regarding finishing a basement.

**Enclosures That Work


Here’s an example of a MSDS data sheet - check out your product…

Chris as far as trapping moisture concerns over the interior tar application how do you see closed cell foam as doing anything different ?

That’s not the way to do things either. You should think about this last quote you just put up. Sorry but that’s just as smart as somebody tarring the inside of the foundation wall.

Power washer and solvent will tak it off. Just a suggestion

When applying closed cell foam at interior the wall Still needs damp proofing/sealed at Exterior side; And the foam will require a thermal barrier sprayed at it’s interior side.

My earlier comment was assuming the wall was only tarred/sealed at interior.

Anyway as everyone has agreed applying the tar at the interior was wrong.