Repointing of Brickwork - Possibly Lime Mortar?

[Holly64]

Hi

I have a bit of water penetration and am certain it is due to some mortar breaking down. The walls are solid (no cavity at all), bricks are yellow stock brick and the bungalow was built late 1940s. I have a feeling the mortar has lime in it. Unfortunately, it's not in my capabilities to do a neat enough job myself so have to get a builder in.

Can I have advice on what questions I need to ask the builder to ensure that he uses the right product? Also I have read not to use a grinder to get out the existing mortar with soft yellow bricks - is this correct? If so, how would the builder get the mortar out to replace it?

Once the wall is repointed I want seal the wall as when it rains really bad, this wall takes a bashing and then I get the water penetration.

Any advice appreciated.

 

[^woody^]

What make you think it is a lime mortar? There is more chance of not than it being lime.

Grinders are fine in suitable hands

The joints need to be raked out to a suitable depth, and then the new mortar properly pressed in and then ironed to a weathering joint - and that gives the water resistance, you wont need any further sealant. Getting someone to do repointing properly, and not done messily too, is getting harder and harder.

If you are minded to seal the wall, then you probably don't need to bother repointing. Use a silane-based water repellent, not a sealer.

 

[Holly64]

Thank you, some of the mortar has come out. I've attached a few pictures of the loose mortar areas. I don't think a repellent would work. This side of the bungalow takes a severe bashing on this side when the rain comes in.

When trying to get a decent trade person to do the repairs, would it be a bricklayer I need?

 

[Mr Chibs]

Looks like it's been 'repointed' before. In the last image, you can see the lime mortar underneath the more modern mortar.
It wasn't raked out properly last time, not deep enough.

 

[Holly64]

Looks like it's been 'repointed' before. In the last image, you can see the lime mortar underneath the more modern mortar.
It wasn't raked out properly last time, not deep enough.

Does this definitely look like lime mortar underneath? I think if this is the case, the modern stuff stops the wall breathing - is this the case? Do I have to get everything done again? Or can I just have those damaged areas sorted out?

 

[Mr Chibs]

I would say it looks like lime based mortar, cement based tend to look more grey on average. Apparently you can tell if there's lime present... by dropping a bit of mortar into some vinegar, if it fizzes a fair bit, it's lime based, cement may fizz slightly. I've tried this before, but couldn't really tell the results.

Most folk will just rake out the affected area, perhaps you need to post a photo showing more of the wall.

Nearly all the old houses I see repointed are done so with cement, lime doesn't seem to get much of a look in for the bulk of jobs.

Are there any damp issues in the house currently?

 

[^woody^]

It does look like lime mortar, over pointed with a strong cement mortar

The issue is not one of breathability but flexibility, and that's why the mortar has cracked and even cracked come of the brick arrises.

Continual cracking is a risk as long as the cement mortar remains, and so consider changing all of it for a lime mix. Raked out at least 20mm. Look for posts from Stuart45 who is the oracle on lime pointing for more details.

 

[Holly64]

Thank you . I will search out his posts.