Spalled Brick Repair

[thiambal]

Hi everyone,

On the front of our house we have a row of soft reds running level with the underside of the stone window cill of the upper window. Two or three of the these bricks are badly damaged and turn to dust at the slightest touch.

I would like repair this damage but am not sure how to tackle it. A builder suggested just slapping in some dyed cement to fill the holes left by the crumbled brick - but I am not altogether convinced.

It would not be too difficult to get the old bricks out as they have crumbled pretty much through the whole depth, but it would be trickey to get whole new bricks in at the window cill drops over the top 1/2 inch of brick.

I cannot really face the old damaged brick with a 1/2 brcik facing as theya re so crumbled to such a depth.

What is the best we to proceed. Could I dye lime motar and fill the hole with this? Or is there anyother better method?

On another note, the builder also advised sealing just the soft reds with a water sealing product to protect against further damage - but I am guessing this is a bad idea!?

Cheers for any advice

Sam

 

[CHRIS]

You could remove the bricks by drilling around each brick and removing the mortar - pull the brick out in one piece if you can then flip it around so the clean face is on show and flush with the wall. if this does not work or you shatter the brick you can get a few reclaimed ones and use an angle grinder to cut them to size (soft reds are very easy to trim down to size) and reset using a lime mortar of the same colour as the original.

give it a few weeks and it will blend in

 

[Lime]

Your description suggests to me that water is running off the window ledge, soaking into the red brick and causing the problem.
Any repair or replacement needs to stop the water penetration.
The sill should have a "drip edge" (a groove running the length of the underside of the sill) that prevents water coming off the sill and running back underneath it. Sometimes this is damaged or blocked up so that it is bridged and allowing water to cross it and run down the wall.
If it were my house I would carefully remove the red bricks (perhaps following CHRIS's idea) and replace them and deal with the sill if it is necessary.

 

[NT]

IIUC the OP is saying they cant replace them because the sill overhangs them, hence no way to get new bricks in there

I'd agree water is the cause, freeze thaw cycles. If you put anything waterproof on them the water will just go into other bricks and they'll follow suit. So you need to fix the water problem, and not prevent evaporation.

Re the bricks, if its really not practical to get a brick in there, a few possible ideas...

1. if the overhang is spaced away from the wall a bit, cut a brick into 2 or more slices, so you get a front slice, a back slice, and maybe more, and fit the slices one after another.

2. Mix red brick dust with lime mortar, lots of the brick.

3. Lime mortar plus red iron oxide powder


NT

 

[Lime]

IIUC the OP is saying they cant replace them because the sill overhangs them, hence no way to get new bricks in there

If I were doing the work I would remove the brick/s below the red course and lower the red brick/s from under the sill.
However I would only do a few at a time for obvious reasons.

 

[thiambal]

I have now been up a ladder and had a good look at the area.

You were right NT there is no drip strip on the undeside of the stone sill so I will need to sort that.

I have had a good look at the bricks and there are actually 10-12 bricks needing attention to one degree or other so not going to be a job for me I think. I will ask our builder and see if he starts making noises about cement.

I have also noticed on closer look at the front of the house and been repointed with cement (cosmetically very well but....). I some places this has failed to bond and can be just pulled out in strips. I thought I would pull it out where it comes away with minimal force and re-point in lime mortar - good move?

 

[NT]

quote="thiambal"

>I have now been up a ladder and had a good look at the area.
>
>You were right NT there is no drip strip on the undeside of the stone sill so I will need to sort that.

Theres more than one way to do that, cutting a groove isnt the only option. But a drip edge/groove/strip wont necessarily solve the wet brick problem.


> I have also noticed on closer look at the front of the house and been repointed with cement (cosmetically very well but....). I some places this has failed to bond and can be just pulled out in strips. I thought I would pull it out where it comes away with minimal force and re-point in lime mortar - good move?

yes.


NT

 

[thiambal]

Theres more than one way to do that, cutting a groove isnt the only option. But a drip edge/groove/strip wont necessarily solve the wet brick problem

Excuse my ignorance - what are the other ways NT?

 

[NT]

Theres more than one way to do that, cutting a groove isnt the only option. But a drip edge/groove/strip wont necessarily solve the wet brick problem

Excuse my ignorance - what are the other ways NT?

One way is to add a bead of something, when the water meets the bead it runs down, and wont run up again. This would be much quicker and easier than making a groove, and doesnt damage or alter the existing fabric.

Another way I've seen work well is to rely on the paint at the front edge, which forms drips at the edge when applied, and this works as the drip 'drips'. I doubt that one would not work in severe weather areas.


NT

 

[thiambal]

Ah ha! right, not sure I understood the paint option but my feeble mind has grasped the bead. I guess a bead of silicon or similar?

 

[NT]

Yes, or whatever material will blend in looks-wise and isnt hydrophobic.

Re the paint drip method, imagine a perfect rectangular block, now you paint the visible surfaces, which includes the front but not the underside, with oil based paint. At the bottom edge of the front you will get a little paint sag/run, and you'll get little driplet shapes and sagged paint shapes along that edge. Thats your dripping point. Minimal but it works.


NT

 

[thiambal]

Ah, I see, yep, I have got the old super computer around that now.

Cheers