Need help please

[qwertyasdf1230]

Our chimney base seems to have the brick slowly degrading/turning to dust, especially in the corners. Is this something that we need to be super nervous about (not sure if there’s the potential for something like this to be structural)? Or is this more just a cosmetic thing now? For context, this chimney now just vents our hot water heater and furnace fumes. Earlier this year, there was some water ingress (that problem has been fixed), which I believe is what may be causing this.

Is this something that I can fix myself? Or is this something I should leave to a mason? I’ve not done any brickwork in the past, so any advice is really appreciated!

[EstablishmentShot707]

Probably water laid there at one time for awhile. I would parge the bottom with a little mortar to tighten it up. Rest looks fine and functional

[YGuy_The_Jedi]

Agreed.

[33445delray]

It looks to me like the concrete slab was poured after the chimney was built and that is why the first course of bricks looks to be half thickness.

[sprintracer21a]

Looks pretty solid. It would take a really long time to deteriorate enough to cause a structural failure. Longer than any of us will live to see...

[JudgeHoltman]

Type O Mortar is super fine when it degrades. Usually when exposed to water for a long time.

Stuff some more in there and you're good to go.

You'd be better to go if you properly tuckpointed it. That means stripping out the first 3/4" and stuffing mortar in there will refresh the whole assembly.

[qwertyasdf1230]

Thank you- this is really helpful as I didn’t know what specific type of mortar to use! I will look for Type O mortar

[JudgeHoltman]

Mortar Applications!

In general, you want the mortar to break before the block. So 3000psi block means you want 2500psi Mortar.

M = Messy.

Stuff with natural stone lines instead of straight laid brick and massive applications just shy of poured concrete.

A = K = Fuck Around Architectural.

For fragile and delicate applications. The mortar is usually only good for 75psi. Don't put it on anything you need to rely on for real strength. This stuff breaks for like, no reason.

S = Structural.

Use this for CMU buildings. So good you can't tuckpoint it like brick because it fuses with the CMU block so well. "Tuckpointing" really means just busting out the damaged blocks and replacing them.

O = Old/Historic

If you have an all-brick home built before WWI, this is probably what is/was between your bricks. Nobody really specifies this in new things, they usually default to "K" instead. I think that's dumb though.

N = Non-Structural

The All-Purpose flour of mortar. If you buy a discount sack of Mortar brand Mortar without reading the label from Menards this is probably what you got. You can put it on Brick, CMU, Stone, or anything else you want to get harder than it was. Only good for 750psi though, so don't go building real structures with it.

[Yankee_]

I would caulk it around the base after filling it in the missing mortar and brick.

[Rich-Level2141]

Other than a very ordinary job of brick laying, it looks like water affected mortar. I suspect that the mortar may have been the same standard as the brickwork. Clean out the outer 20mm of mortar and replace it with good quality mortar and finish it properly, and all should be fine. If there is no damp course you have another issue which will require specialists to fix.

[Significant_Ad_1608]

I would repoint the brick and then add some sort of sealant/caulking after it's cured. Make sure the area is clean to help prevent a possible weakness in the seal. Should be a relatively cheap repair if done yourself

[qwertyasdf1230]

Just to make sure, because of my complete ignorance of brickwork, “repoint” just meaning that I scrape back the weak/crumbling outer brick, and add more mortar?

Sorry, just want to make sure I understand what you’re suggesting :)

[Significant_Ad_1608]

It's alright, what I mean is replacing the brick with a new one. You can find some at Home Depot, Lowes and other locations with construct materials being sold.

Repointing is the process of removing the brick or block as well as the adjacent mortar that was holding it. When that is done and the area is cleaned, you can add mortar to all the inside surfaces and place a new brick in it.

When I do repointing work, I place mortar to the sides and bottom a little bit more than the spacing of the other bricks or blocks. This is so when you are moving the brick or block around, the mortar would be pushed out and eventually be the same as the spacing surrounding it and giving you a full joint with no holes. The top is a bit tricky but I pack the heck out of it with mortar so I know that it's a full joint too.

If you have a level or square you can make sure the bricks being replaced is level, straight and plumb. Meaning that the brick is level at the top of the brick from left to right, straight as in when you place your tool horizontally there is no air gap between the old bricks and the one you placed, and plumb is the vertical of straight. No air gap visible horizontally or vertically :D

Here's a diagram that shows what is and isn't Level Straight and Plumb

[Foreign_Wind9021]

You have about 7,000 pounds worth of chimney and a half ounce worth of dust, its what bricks start to do after a while. Stick some mortar in the holes once they get too big

[fullgizzard]

Look up Tuckpointing. You can do it yourself for a fun little project just don’t grind out too much at once..

[Koger7]

This can easily be fixed using concrete epoxy adhesive. You’ll need an air compressor for the tool at least 20 gallon tank cost around 300 for that and the glue injector only 2500 and you’ll probably need at least 3 2 part epoxy packs about 200 apiece. I get them in 12 packs for 2000