Cracks in basement foundation walls and floor

noah_2008September 26, 2010

Hi all. I would appreciate some advice on this issue as I am getting conflicting opinions from local contractors.

I have just moved into an 8 year old house and we are looking at finishing the basement. The floor of the basement has 3 long cracks, each very narrow (1-2 millimetres at the most) with no shifting or lifting of the floor anywhere. Additionally, there are 4 very narrow cracks in the walls of the poured foundation which are visible on the inside and the outside (where they continue above ground level). The cracks in the walls are also very narrow (really just hairline cracks), but they appear to go right through the wall.

Being a fairly new house, the foundation has a properly functioning weeping tile and a dimpled plastic membrane surrounding the foundation. There is no evidence of water ingress anywhere in the basement despite heavy rainfalls and despite all the cracks.

The question is: do we need to repair the cracks prior to finishing the basement (floor and wall)? If so, what is the best approach to fixing them?

I have talked to several contractors who have told me that the cracks do not need to be repaired because the waterproofing membrane and weeping tile will prevent hydrostatic pressure from building up, thereby preventing a leak through the foundation cracks. I am really not sure whether I trust this advice.

Any insight from forum members?

Thank you for reporting this comment. Undo

These are settlement cracks of no significance. The performance guidelines I build under require no repairs to any cracks in concrete floors or poured foundation walls that are less than 6 mm. (See link below, pp.24-28.)

Were the wall cracks wider, the standard repair would be epoxy injection.

Epoxy injection used to repair minor cracks in new home foundation.
Photo: Heather Joy Investments

Here is a link that might be useful: Construction Performance Guidelines

    Bookmark   September 26, 2010 at 2:49PM
Thank you for reporting this comment. Undo

Would you recommend undertaking the epoxy repair just to be on the safe side? (before finishing the basement, since once I finish the walls, I can no longer monitor the status of the cracks)

    Bookmark   September 27, 2010 at 9:30AM
Thank you for reporting this comment. Undo

If that's all that's happened after eight years, I wouldn't bother. You might want to note though where the wall cracks are, just in case. They usually appear at the window corners, as in the photo above.

    Bookmark   September 27, 2010 at 9:35PM
Thank you for reporting this comment. Undo

We just had our cracks and rod holes repaired in preparation for finishing the basement. It cost $1,000. Only one of our cracks ever leaked and only when it rained super hard.

    Bookmark   October 11, 2010 at 12:35PM
Thank you for reporting this comment. Undo

Excellent advice from the pros.
Concrete will crack unless the quality is extraordinary and higher.
IMO, as an amateur, I would assure that 99.9% of the rainwater flows away from the house at least 3 to 4 feet.
Also, if the crack is too narrow, the epoxy cannot flow. Maybe a paint???

    Bookmark   October 13, 2010 at 1:48PM
Sign Up to comment
More Discussions
basement flooring - tile or finished concrete
we're planning a reno that will include expanding and...
ideas for basement?
Hoping some of you more creative people can help me...
Michael Oslosky
What to do with old cistern room?
The house I'm buying has a weird feature. There's a...
Str'l Wood Floor + CrwlSpace vs Concrete Slab
Hello, We were discussing our plans with a builder...
What kind of ceiling to do?
We are wanting to finish out basement rustic/lodge...
Sponsored Products
Charlotte Cheval 63" High Floor Mirror
Lamps Plus
Area Rug: Rain Kaleidoscope 5' x 8'
$98.97 | Home Depot
AM2C Floor Lamp by Nemo
$1,747.20 | Lumens
Huppe | SWAN Floor Mirror
Cape Cod Area Rug
Home Decorators Collection
White Rochelle Swivel Armless Bar Stool
Zuri Furniture
Pet Ego Sun Blossoms Bed - SUBL M
$47.00 | Hayneedle
Hyper Links Giclee Glow Bronze Club Floor Lamp
Lamps Plus
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™