Using cement mortar for soft red bricks in an Edwardian house is it ok?

[george75]

Some bricks have been laid in a wall of 1910's house and the brickie used a cement only mortar. Is this ok?

 

[opps]

A friend of mine is a pointer.

He only uses lime if the client is willing to pay the premium. Lime is much more expensive and stains the red "rubber" bricks. You then need to use acid or stain to eliminate the 2 to 3 mm stains at the edge of the bricks.

I have only known him for a couple of years but I have seen sand/cement only jobs that he did 15 to 20 years ago and there is no evidence of brick damage.

Most of those properties are Victorian and when built would have had lime mortar.

 

[george75]

A friend of mine is a pointer.

He only uses lime if the client is willing to pay the premium. Lime is much more expensive and stains the red "rubber" bricks. You then need to use acid or stain to eliminate the 2 to 3 mm stains at the edge of the bricks.

I have only known him for a couple of years but I have seen sand/cement only jobs that he did 15 to 20 years ago and there is no evidence of brick damage.

Most of those properties are Victorian and when built would have had lime mortar.

I'd have preferred a mortar with some lime

 

[stuart45]

The general rule of thumb for repointing is that you use a similar but slightly weaker mix to the original. For a house built in lime mortar it should really be lime.
However there are plenty of old houses that have been repointed with cement mortar without any apparent problems, but there are also some that show signs of damage.
I always repoint with lime mortar myself when the original is lime, usually finishing the joints with the churn brush.

 

[george75]

The general rule of thumb for repointing is that you use a similar but slightly weaker mix to the original. For a house built in lime mortar it should really be lime.
However there are plenty of old houses that have been repointed with cement mortar without any apparent problems, but there are also some that show signs of damage.
I always repoint with lime mortar myself when the original is lime, usually finishing the joints with the churn brush.

the work done was bricklaying and not re pointing, does this make a difference?

 

[stuart45]

Mortar should be weaker than the brickwork so that any movement in the walls will crack through the joints and not the bricks. Moisture can pass through lime joints better so the walls can ' breathe' which helps any damp issues. Lime mortar can also self heal if the joints crack.
When you mix lime mortar it needs to be mixed up in the mixer for about 20 minutes, then left for 20 minutes, then mixed for a couple more. This gets plenty of air into the mix making it workable without too much water added.
If this in not done too much water is needed in the mix to make it workable and this is why people are getting some staining.
I'm not sure if it's a good idea to take all the work out if it looks OK though, as you may well find there won't be any problems.
Years ago it was quite normal to replace the brickwork on old houses with cement mortar.

 

[george75]

Mortar should be weaker than the brickwork so that any movement in the walls will crack through the joints and not the bricks. Moisture can pass through lime joints better so the walls can ' breathe' which helps any damp issues. Lime mortar can also self heal if the joints crack.
When you mix lime mortar it needs to be mixed up in the mixer for about 20 minutes, then left for 20 minutes, then mixed for a couple more. This gets plenty of air into the mix making it workable without too much water added.
If this in not done too much water is needed in the mix to make it workable and this is why people are getting some staining.
I'm not sure if it's a good idea to take all the work out if it looks OK though, as you may well find there won't be any problems.
Years ago it was quite normal to replace the brickwork on old houses with cement mortar.

Would a weaker cement mortar be breathable?

 

[stuart45]

A lot of good site bricklayers don't know about the use of lime mortar. Years ago when I was an apprentice we were taught at Tech to use a 3/1 sand/cement mix for repointing as it was thought that a strong mix would last longer.
However in recent years it has been found that these strong mixes can sometimes damage the brickwork. This is especially true with old soft bricks where they are exposed to a lot of the freeze/thaw cycles which tend to break away the edges of the brickwork.
If your bricklayer has used say a 1/1/6 cement/lime/sand mix then the brickwork may well be OK, especially if it's sheltered.

 

[george75]

This is especially true with old soft bricks where they are exposed to a lot of the freeze/thaw cycles which tend to break away the edges of the brickwork.If your bricklayer has used say a 1/1/6 cement/lime/sand mix then the brickwork may well be OK, especially if it's sheltered.

No lime was used at all

 

[stuart45]

The weaker the cement mix the more it allows moisture through. The really strong mortars seem to do the most damage.

 

[george75]

That should allow the bricks and wall to breath