Lime pointing failed?

[ben81]

We had the back wall, gable end and chimney repointed in Dec and Jan (bad time of year to do it I've since found out!). Is the white deposits in some areas a result of water getting in and the lime coming out before it had a chance to harden? And is it likely to fail as soon as temperatures drop below freezing?

Or is it just a natural part of the hardening process?

The brickie is coming to have a look and the firm has said they will sort any issues. Down there will be easy enough but the gable end and chimney will be harder to access as theres a large single story extension attached to it.

 

[Zebra]

What did they do? That looks like the worst pointing ever. Did they rake out the old or just smear some on top? Did they use lime or cement? Did they only do that white patch under the window? It looks like the cement pointing is still there underneath and something white has been smeared over the top. And it's completely uneven and blotchy.

 

[Drayton]

I'm no sort of expert at all but that looks more like white paint on cement pointing than anything else I can think of! (And absolutely horrendous pointing at that...) Did the white just slowly appear over time, or was it all white to start with, or...?

 

[ben81]

They raked out the whole wall and repointed with pre-mixed dark grey lime. The white appeared over the last couple of weeks in some areas only.

 

[ben81]

This is shortly after theyd finished, before the white appeared

 

[Feltwell]

I know it's not what you want to hear, but that does not look like a good job. It looks like they were trying to do weatherstruck - full & flush like on this link would have been better on less than perfect brickwork (I admit to bias - the chimneys are mine):-

https://www.periodproperty.co.uk/forum/threads/chimney-works.16671/

However, why have you got white deposits now? Well, I'd say it's not just damp coming out, that just appears darker. It could be salts in a wet wall evaporating off from the surface. Does the white brush off?

Are you 100% sure the builders used a tinted pure lime mix, no cement?

 

[Lacan07]

They raked out the whole wall and repointed with pre-mixed dark grey lime. The white appeared over the last couple of weeks in some areas only.

So it came in powdered form and they added water? Can you remember the name of the product?

How cold was it when they did this, can you remember any frosty evenings, etc? It seems like the lime may not have set and is now seeping out. If this was the case you'd expect the joint be soft and crumbly, have you tested this?

Unfortunately repointing is never going to look great as the joints are always going to be thicker, especially as with lime its good practice to fill so the joint is flush with the wall allowing no water to settle.

 

[stuart45]

If a black dye was added to the mix, it will go grey.as it dries and cures.
NHL 3.5 is normally quite reliable. It would have been better to finish with the churn brush.

 

[ben81]

Yeah it was Lime Green brand, says pure lime on the bag and it's the medium stuff. I still have a bag left in the garage. With a bit of effort it's fading away with a brush but I dont know if that's me just taking the surface of the pointing off! It feels hard to touch but I just tried scraping bits out with my key and its coming away whereas the grey bits aren't

There was frost some nights while it was being done, then we got 2 or 3 weeks solid of rain shortly after theyd finished. That wall gets the driving rain too.

I wonder if its leaching or efflorescence? This is a big worry! Ill get in touch with them, looks like they're going to have to come back, rake those bits out and redo it in March when it warms up a little

 

[ben81]

Yeah the front of the house which is mostly the original mortar is the same colour so they got it to match

 

[Zebra]

Frost while it's being done is bad news. Temperatures below 5 degrees while it's being done are bad news. Did they at least cover it overnight with something to keep the finished faces from freezing?

 

[ben81]

They did on some bits but not all, I'm pretty sure that bit under the window wasnt covered.

 

[stuart45]

When you use a metal tool on either cement or lime mortar to finish the joints, it brings laitance to the surface, and will form a more watertight skin of either pure lime or cement. With cement mortar it's usually preferred, but with lime it prevents carbon dioxide getting through.
Weather struck joints are quite difficult to do, especially in older, chipped.brickwork. Nowadays, even on new work, flush joints are used with irregular shaped bricks.

 

[Feltwell]

The Lime Green mortar is, in my opinion, good stuff -it's what I used for my house. Stuart's comment above is very valid, a flush joint, beaten back with a churn brush when semi-dry, would have looked like this:-





I suspect your white staining is just some efflorescence - in which case, if you're OK with the appearance of the weatherstruck pointing otherwise, just leave it and it will gradually weather off. You can give it a brush with a stiff brush if you like, that can help to take it off the surface a bit. It'll stop only when the salts in the bricks or mortar are all gone, which can take a while. I had some here on the same pointing style as done above, took 2-3 years to stop.

To be honest it looks to me like you've had repointing done by a builder who is only used to working with cement, so whilst he's used lime this time he's also used the same techniques he'd use for cement.

 

[ben81]

I can live with the actual pointing, it's a hell of an improvement over what it looked like when we moved in! There were holes all over the place, various different coloured cements, more spalled bricks and the previous owner had smeared some cement over old mortar without taking out managing to get most of in the brickfaces too.

My main concern is it failing and crumbling out. If the white goes over time and the mortar lasts longer than me I'll he happy enough

 

[Feltwell]

If it's not loose and crumbly I reckon you'll be OK. That Lime Green mortar goes hard pretty quickly.

 

[ben81]

Thanks for all your input everyone. Fingers crossed it's ok aside from the poor workmanship. I'll just tell everyone its rustic.

 

[stuart45]

It could well dry out the same colour over the whole area, and then in time the joints will weather back slightly to expose the aggregate, changing the colour slightly. You can see this on modern houses, when first built the joints are a grey cement colour, and after a number of years develop a more sandy shade.
When repointing a building, apart from getting the correct mix, it's worth considering the finished colour.
The style of pointing is also important, I can think.of around 20 different types, and only a few are suitable for certain walls.

 

[Lacan07]

The Lime Green mortar is, in my opinion, good stuff -it's what I used for my house. Stuart's comment above is very valid, a flush joint, beaten back with a churn brush when semi-dry, would have looked like this:-

View attachment 10128

View attachment 10129

I suspect your white staining is just some efflorescence - in which case, if you're OK with the appearance of the weatherstruck pointing otherwise, just leave it and it will gradually weather off. You can give it a brush with a stiff brush if you like, that can help to take it off the surface a bit. It'll stop only when the salts in the bricks or mortar are all gone, which can take a while. I had some here on the same pointing style as done above, took 2-3 years to stop.

To be honest it looks to me like you've had repointing done by a builder who is only used to working with cement, so whilst he's used lime this time he's also used the same techniques he'd use for cement.

That's exactly how a lime repointed wall should look imo.

The problem arises in when you have a mix of joints - perfectly decent original lime joints, poor condition original joints, and a large smattering of cemented joints. The question is do you do the whole house to achieve a consistent look or do you suffer the look of fat and thin joints.

 

[Feltwell]

That's exactly how a lime repointed wall should look imo.

The problem arises in when you have a mix of joints - perfectly decent original lime joints, poor condition original joints, and a large smattering of cemented joints. The question is do you do the whole house to achieve a consistent look or do you suffer the look of fat and thin joints.

Well, the pictures are of my house - which previously was a mix of knackered lime joints, neat but cement joints, cement joints smeared on by a drunken 5 year old, cement joints with red tint in (weirdly, in odd patches on the front of the house) - combined with some spalled bricks, and plenty of bricks where old pipes etc had been drilled through.

I repointed the whole house, and replaced all the damaged bricks. The front of the house is a different, better quality brick with very thin joints - I had one finger trowel ground down to only 1mm wide to do some of them! The angle grinder was kept strictly away from the front of the house, raking out was by hand with a plugging chisel or air hammer with homemade plugging chisel only - luckily the brick was very hard so the cement parted company OK.

The pictures you can see above are of the side and rear of the house, done in a much wider jointed, softer common brick. This was raked out carefully with a grinder - where it was cement pointed if anything doing it by hand did more damage, it took the corners off the bricks. Even so, the joints are a bit wider now then they were before, you just can't help it. I don't really subscribe to the "you should never rake out with a grinder" theory, where you've got hard cement pointing that is well stuck then CAREFUL work with a grinder with a good diamond disc on will do far less damage than a plugging chisel.

My consolation is, with the whole house being done now, including the chimney stacks, it should be a century or so before so much work is needed again - and next time it will be much easier for someone to rake out.