Spalling Brick

[pgoodcake]

Hello,

Has anyone encountered and repaired spalling brick? The house in question was built between 1920 - 1940.

Thanks for your help!!!

[GibsonGM]

Hi Cake,

Yup, that's not uncommon! Probably due to freeze/thaw cycles over the years. Sometimes and entire structure will do it! Hopefully it's just localized in your case, related to how the brick fired in the kiln way back when (voids).

The repair for 'blown out brick' isn't hard. You carefully score around it with a chisel (or grinder, if you feel skilled), ease out the old brick. Clean up the hole, dampen it, and re-bed a matching brick in the spot. Tool the joints, keep lightly damp (mist spray bottle) for a few hrs, done. If you want authenticity you can try to match the mortar. There are (powdered) dyes available at masonry supply houses that you mix into the mortar,first making samples and allowing them to dry to see if they match. Check Youtube, "replacing faulty brick" or some such.

Real mortar will be composed of clean, fine mason's sand, lime, and portland cement - the proportions will determine the color of the final product. Do some research on that, a little learning is a great thing in this case I was a mason for 14 yrs and have done MANY of these repairs - they're easy once you get the hang.

If possible, once the patch is dry (couple months...) one could apply a sealer to the wall to hopefully stop this from becoming 'a thing'. You could ask a local mason for an inspection/advice, that might be a good idea! Good you're looking into it before it's a 'big thing'.

~Mike

[pgoodcake]

Thanks for your help Mike!

[Gothichome]

Pg, I responded to your post on the Period Property site, Mikes response is spot on, although I must disagree with his recommendation to seal the bricks. Sealing the bricks involves usually spraying a moisture barrier to prevent moisture getting into the brick, the other side of this coin is any moisture that does get in can’t get out. Freeze thaw cycles will spall the brick one again and now you have a whole wall of potential spalling. Your bricks are a hundred years old and have held up well over all, and may still last another hundred years as is.

Ron

[GibsonGM]

There's decent logic behind not sealing. My viewpoint is just that as water continues to infiltrate the brick, it'll find voids and freeze in them, perhaps leading to more of this. That's what the masons in my area would recommend, anyway...I was one for 12 years, lol. I don't have the long-term info about happens years later, though - never went back to see how things are doing a decade later.

It's possible the spalling could've been caused by other factors, like a faulty drip edge or something allowing the wall to get soaked...or even be a one-off, a 'bad brick' from the kiln.
That's why I suggested getting a mason's opinion; they can stand on-site and really get a sense of the conditions. Probing other bricks might reveal others that are porous, are put that thought to bed.

Small quantities of moisture getting in brick will be absorbed 'throughout its structure', as they'd say about dense-pack cellulose. Bulk water blows them out. Never heard of sealing masonry causing an issue, but perhaps if one didn't re-apply every few years, you could encounter this as it broke down naturally...as with everything 'old home', studying the problem and not jumping is usually the best way to start!

[Gothichome]

Mike, I think you may be correct in thinking water managed to get deep into the brick and maybe collected in a void, froze and blew out the face. Pg’s wall looks to be a soft brick with lime mortar so it should have breathed easily. The water may have got that beep into the brick via liquid water seeping between the mortar and the brick. PG, under what conditions did the brick spall?

[mjt]

For our 1895 built house, we did the same as what Mike has already said. We had a mason who specialized in old houses do it as part of a larger tuckpointing exercise on each side of the house (one side per year as it was a somewhat expensive proposition). While he re-tuckpointed, he replaced spalled or cracked brick where necessary. In general the process was to removed loose or failing mortar using hand or power tools and tuckpoint with new. for brick replacement, all the mortar was removed.

Finding matching brick that was in stock and approved by the Historic Preservation Commission was the hardest part. We finally found some that was almost the correct size; it needed a half inch or so cut off one end.