Thermal Bulging walls

[Dan Merrell, CMI]

I was at an inspection today at a newer home. The owner has a problem with a wall that bulges when the weather gets very cold. The builder and new home owner warranty person said that this is very common. It is called "Thermal bulging". I have never heard of it. Has any one else ever heard of this?

[James E. Braun, CMI]

Never heard of thermal bulging, but it sounds like a lot of water is ponding and freezing against the wall on the outside.

[Chuck Evans]

Apparently Google has never heard of the term in this context either. At least not prior to this thread. I would ask the builder/warranty rep. to produce bona-fide documentation regarding said common phenomenon.

I'm curious to hear more about what is happening. Any pics or details on how much bulge at what kind of temps, etc.?

[Wayne B. Wilson]

Only in Canada Eh.
Just kidding pictures would be good.

[Dan Merrell, CMI]

It is an open wall on the outside. There is no soil contact at all. I think the builder and new home warranty is trying to get out of repairs.. There are no pictures. When I was there it was not cold enough for anything to happen.

[Dan Merrell, CMI]

Thanks for everyones imput..

[Wayne B. Wilson]

what type of siding?

[Christopher Currins]

Above-ground masonry walls

Bulging of walls. Masonry walls sometimes show signs of bulging as they age. A wall itself may bulge, or the bulge may only be in the outer withe. Bulging often takes place so slowly that the masonry doesnt crack, and therefore it may go unnoticed over a long period of time. The bulging of the whole wall is usually due to thermal or moisture expansion of the walls outer surface, or to contraction of the inner withe. This expansion is not completely reversible because once the wall and its associated structural components are pushed out of place, they can rarely be completely pulled back to their original positions.

The effects of the cyclical expansion of the wall are cumulative, and after many years the wall will show a detectable bulge. Inside the building, separation cracks will occur on the inside face of the wall at floors, walls, and ceilings. Bulging of only the outer masonry withe is usually due to the same gradual process of thermal or moisture expansion: masonry debris accumulates behind the bulge and prevents the course from returning to its original position.

In very old buildings, small wall bulges may result from the decay and collapse of an internal wood lintel or wood-bonding course, which can cause the inner course to settle and the outer course to bulge outward. When wall bulges occur in solid masonry walls, the walls may be insufficiently tied to the structure or their mortar may have lost its bond strength. Large bulges must be tied back to the structure; the star-shaped anchors on the exterior of masonry walls of many older buildings are examples of such ties (check with local building ordinances on their use).

Small bulges in the outer masonry course often can be pinned to the inner course or dismantled and rebuilt.

[Brian E. Kelly]

Good Info Chris.


on a side note, every now and then even at my advanced age, I still experience "Thermal Bulging" myself, usually brought on when in close proximity to HOT Women.

[Joseph W. Keresztury]

Christopher, Good info (aging walls) but Dan was talking about a New Home, so it doesn't sound realistic, with his situation. But then again, I'm not in Canada.
Brian, your bulging is to small to be considered even though the hot women think your hot

[Brian A. MacNeish]

Originally Posted by dmerrell

I was at an inspection today at a newer home. The owner has a problem with a wall that bulges when the weather gets very cold. The builder and new home owner warranty person said that this is very common. It is called "Thermal bulging". I have never heard of it. Has any one else ever heard of this?

Yepp!! In R2000 houses with the thicker walls. Have seen it along kitchen countertop backsplashes which are perfectly straight.....usually no more than 3/16-1/4" gap at most.

Similar to bowing steel slab doors up north that needed Foamguard weatherstripping to maintain an airseal or attic truss uplift occurring with the advent of higher insulation levels in attics.