Repointing workers sanded brickwork

[Jellyfox]

Hi,

Our 1920s house has had issues with damp, we had a survery done which recommended removing the concrete render and repointing with lime mortar.

When the contractor stripped the render away it came off unevenly, and the bricks were in poor condition underneath.

To remove the most stubborn render and make everything uniform they sanded / grinded the face of all the bricks level

I'm really concerned this has damaged the bricks - any advice would be a massive help!

 

[Kearn]

Pics would help to understand the extent of this damage.

But that sounds like terrible trades.

Have you a solid or cavity wall, your property is at the age where it could be either.

If there was damp, I’d assume solid.

Don’t let this ‘contractor’ do any more damage to your building.

What they have done is remove the very important fire skin on your bricks, the harder outside surface. Now they will be very porous and potentially quite crumbly depending on their make up.

Worse case scenario:
It means you will no longer be able to simply repoint, it will firstly look terrible due to the damage, and the bricks will be like sponges and deteriorate further.
Therefore you now need to lime render.

Whether this is salvageable with some brick replacements and a repoint or a full render, you need to find someone capable and experienced.

It’s not uncommon for the bricks under an inappropriate render to fail and lose their skins with the render when it’s removed. So some of the damage may have already been done for king your hand to a re-render in like.

Regardless, do not let this person touch your building any further.
And depending on your contract and scope of agreed works, withhold money as they have done damage to your property which will cost far more to rectify.

 

[stuart45]

It's become more common in the London area in recent years for some companies to sand down London stock bricks. The effect of this won't really show up for the initial few years, but the long term might bring some rapid deterioration. It's a relatively new idea, as the machinery to do the work is more available now.
Years ago sanding down face bricks was unknown, apart from special rubbing bricks for gauged brickwork.

 

[Jellyfox]

Thanks Both,

This seems a common practice in the area, I've visited and spoken to several others who've had the same done, luckily no issues with deterioration to their bricks so far over the last couple of years.

We're in a bit of a bind, may have to wait and see and re-render if the bricks spall in the coming years.

 

[stuart45]

I'm surprised they didn't discuss the idea of sanding before they started the work. It's well known that when removing OPC render that the chances of the brickwork being damaged are high.
However, you may well find that provided the correct mortar is used there won't be a problem. If this method had been in use for 100 years there would be more info about the long term effects. The problem in the construction industry is that it can take many years to discover whether the correct methods have been used.

 

[Stevers]

It looks like the new bricks under at least one of the windows have 'broken the bond' since it looks like that unusual bond should be symmetrical on each face of the bay. It shouldn't take much longer on what will be an expensive project to get it right! I'm also wondering if some of those header bricks were once corbelled out to support the cills as a feature, and that anything sticking out was knocked off when the OPC render was applied.