LBC brickwork renovation proposal suggestions

[overlander matt]

We recently put in an application for listed building consent for work on our Georgian house. One of the things we would like to do is to replace a lot of the damaged bricks on the front of the house (and elsewhere) and put right some particularly poor quality repairs. In total, I have estimated around 240 bricks need replacing and mainly at a higher level which requires scaffolding. As we have a few repairs to do up top to the cornice, leadwork and roof then I am keen to take advantage of the scaffold for as much work as possible.



The house has previously been repointed with cement based mortar which may be responsible for some of the damage to the brickwork. As we have the scaffold I would be keen to see if we can repoint the entire front of the house... If not then at least the very highest section which would not be possible to reach in future without a proper scaffold. I have been asked by the new CO to provide a justification for this and to prepare a trial panel for inspection. It seems there is a reluctance to approve repointing of whole elevations due to damage this will most likely cause to the brickwork... I'm not sure what is the greater evil - the cement or the repair work.

On the plus side, the cement mortar looks fairly old on this elevation and is not very deep. It seems that it can be removed without too much effort and could even avoid the use of the dreaded angle grinder (amusingly the listed barn currently under conversion next door is covered with tell tale angle grinder dust patterns). I was going to suggest that we use a repair section as the trial panel - we have reclaimed bricks that look a decent match but will need to specify a suitable lime mortar. I like the idea of the consistency we will get from a premixed mortar but it is difficult to know what the right one is given the absence of original mortar on the front (and other elevations). I did manage to uncover a couple of areas that show the colour and pointing style but this was at the rear of the property.




I was going to try out a Lime Green product supposedly for finer joints... The pointing looks to have a ruled line between the bricks (not sure what that is called).

https://www.lincolnshirelime.co.uk/lime-green-chalk-coloured-lime-mortar-nhl-35-25kg-for-fine-sized-joints-3544-p.asp

If anyone has any suggestions on the above plan that would be much appreciated.

Thanks,

Matt

 

[Feltwell]

You may well find that some of the damaged bricks can be taken out and turned round rather than replaced.

A bit of digging with a plugging chisel should give you what the original mortar colour was.

 

[TheForge]

Are the lines in the mortar coloured?

If they’re simply lined this is known as ruled or sometimes penny struck pointing. If they’re coloured differently to the mortar (historically often with a white distemper), this is called pencilling or tuck pointing.

Are you certain the front is cement pointed? It looks a very neat job and difficult to tell from the photo. Do you have a close up?

NHL3.5 is, in my opinion, too ‘strong’ for historic brick work and will set too hard and continue to gather strength over many years. See recent research by Historic England https://historicengland.org.uk/content/docs/research/hydraulic-lime-production-bcd18pdf/

Lime putty based or NHL2 mortar would be more appropriate. A wet pre-mixed lime putty mortar would be quicker to use and avoid site mixing.

 

[88v8]

Our local stonemason who does a lot of resto work, is chary of part repointing due to the difficulty of matching colour and texture.
On a rubble cottage such as ours this is not a big deal, but on a more formal house such as yours, I suspect that you would see the delineation were you to repoint only the top.

I had to match some pointing recently, made up multiple test strips of different ratios of different sands and limes, I got lucky.

Can understand the CO's reservations about removing cement from soft reds. Perhaps a hands-on demo will help.
Angle grinder. Arrrgh !

Ivor

 

[plasticpigeon]

The reciprocating mortar saws like an arbortech are more controllable than an angle grinder. An angle grinder can cut through a red brick with ease and it is all too easy to cause a lot of damage.

 

[overlander matt]

Thanks for the thoughts on the repointing. It's a bit of a dilemma what to do here - I'm keen to maximise the use of the scaffold for as much as we can manage. The majority of the brickwork needing repair is at the top so it seems an obvious choice to repoint the area if the conservation officer approves... As the scaffold is going up tomorrow I should get a better look at the condition of the bricks and the pointing which is a bit thicker than lower down.

I took a photo of a good section of the brickwork lower down - generally this is in better condition but the pointing is fairly loose. It's not very deep here either at approximately 5mm. Were all the pointing of this standard and condition then I would probably not be in any rush but we obviously need to repoint and repair sections elsewhere and so I need to choose a suitable mortar for this. Getting pre-mixed should help with consistency should we have to do the repointing in stages. Given the absence of any existing original mortar on the front and side elevations, I can pretty much take my pick.



As for the angle grinder, I must admit this did get used on a section round the back for some fine joints... we did try a reciprocating saw but on this part of the house the joints are a bit thin to accommodate it. Would be good to know how it behaves on wider joints.

Thanks once again. Advice is much appreciated.

Matt

 

[Abi Cott]

Apply for LBC to repoint the entire facade. That LBC lasts two years initially, but is then essentially endless once you have "substantially" started work. That would allow you to start the work on the areas accessible from the scaffolding, and then complete the lower areas at a later date once the funds are in place, and might receive a warmer welcome than an application to repoint part of the facade.

 

[overlander matt]

Time for a quick update, the scaffold started to go up around the front of the house which has allowed the first close-up inspection of the brickwork higher up...



It's fair to say there is a good mix of brickwork in need of repair, cementitious pointing I would be keen to remove, poor repairs to be put right and a few cracks to the side of the house. Hopefully I can permission to repoint the whole lot and if we only manage the top section then at least it's a start.




I was a bit surprised to see the top of the central sash window had dropped leaving a significant void above it. I hadn't really noticed that from ground level so that will be a good thing to put right. It will be a busy 6 week hire period with the scaffold.

Thanks again for the advice.

Matt

 

[overlander matt]

An update on the repointing...

My request to repoint the front of the house was met by a request from the council to prepare a trial patch in a discrete location. As we had some repairs to carry out to the front of the house I thought we would point up an area of approximately a square metre where the repairs were completed. I am at the point of approaching the council for a decision on this. My impression is that the default position of conservation officers is to avoid repointing so I want to make the strongest possible case for repointing.

The cement pointing is actually quite easy to remove with a hammer and pointed chisel. So far there has been little damage to the brickwork. If the council objects to repointing of walls with cementitous pointing on the grounds that the brickwork will be damaged then surely preparing a patch showing the bricks free of cement mortar and damage should be sufficient. The first photo shows a section with the old pointing removed





Once the brickwork has been repointed the joints look fatter. Presumably this is just a matter of the lime mortar being flush with the brickwork rather than recessed a little and over time this will weather back in. I would be keen to know whether the pointing shown in the photo looks acceptable. I need to present something to the CO shortly in support of my request. Essentially more than 90% of the house has been repointed with cement and we want to try to reverse this. Sadly there is very little original pointing on show so little evidence exists for what we need to match the new pointing to.

The previous CO suuggested that repointing up to 20% of an elevation could be considered a repair not requiring LBC. Does that sound reasonable? As I have the house scaffolded I am keen to get as much pointing done as possible while we have it. At the very least it would be good to get the highest areas repointed and tackle the lower areas from a scaffold town in future. In which case I would be looking to repoint the top 20% of the elevation. I'm wondering whether I am overstepping the mark here...

Thanks for any comments/thoughts on the above.

Matt

 

[88v8]

As an aside, in your earlier photo there is a nice example of a flat 'arch'. But it still looks like an arch because the bricks are shaped as voussoirs. A world away from soldiers.
Did you ever find why there was that void beneath the brickwork? Perhaps just because the bottom was uneven? A flat arch is a difficult thing to do well.

Sorry, but that new pointing looks like Mr Blobby. Bricks floating in a sea of lime.
I think it should have been rubbed back off the face with hessian as the work was progressing. Allow to dry enough that it won't smear, then rub off. Slow, but a necessary element in fine gauged brickwork.

Ivor

 

[Kearn]

I wouldn't personally show that section to a CO - or repoint any more in the same manner. The lime is too prominent in thickness, it shouldn't be overpowering the bricks visually. Yes it is a few shades lighter and brighter, but it's the amount that shifts the appearance away from what should be delicate and finely finished Georgian brickwork. It doesn't look like listed building worthy craftsmanship.
You've shown previous original pointing, one section which looks like smart penny pointing - is there a reason your new pointing hasn't referenced this, or the other original section, in stlye? I'd expect that approach to carry much more weight with your CO. And will do your beautiful building the justice it deserves.

 

[overlander matt]

Thanks for your comments Ivor and Kearn. I wasn't too happy with this work and we won't be continuing with this approach... It's very frustrating given the amount of discussion about how important it was to get the pointing right. It certainly won't win any favour with the CO. In terms of removing the lime mortar from the bricks, is there anything we can do?

The front of the house has fine joints (approximately 6mm) up to the top of the first floor windows then the joints are significantly wider (>10mm). This top section has cement pointing and I feel this can be improved by its removal and repointing within the reasonably well defined margins of the brick edges. The old pointing can be removed easily enough and the bricks are undamaged. As for the pointing detail, the struck pointing shown earlier was at the rear of the house with wider joints and it's unclear whether this detail would have been used on the front. A check on some nearby properties of similar scale and vintage show plain pointing. We went with a lime mix from Anglian Lime. The colour is not too far off what is hidden elsewhere around the house albeit a bit bright right now.

Elsewhere on the house (see the photo with the red coloured pointing), the brick condition is worse and even the cement pointing is falling out. Joints will invariably appear wider where brick erosion has occurred if one points flush to the face of the brick... Any suggestions about how to approach repointing weathered areas?


As for the rubbed arch, the photo shows the worst one of the 9 we have. The water gully collecting the rainwater from the front of the house is directly above and presumably is responsible for the localised brick damage and the arch below. Regarding the gap, the window frame is not square - it was 2.5cm lower on the RHS!

Thanks once again. I did like the Mr Blobby reference Ivor.

Matt

 

[88v8]

Get the mortar off..... Depending on the mortar mix and how quickly it's gone off, and how soft the bricks are, you may just be able to go at it with a wire brush or a paint scraping triangle, but I suspect the easiest thing would be to remove it completely while it is [relatively] soft and start again. It would be tricky to just knock the mortar off the bricks without leaving a ragged edge in the pointing.

Apparently the pointing you need is called Tuckpointing.
It's evidently not that easy, so much so that here is a company that specialises in it.
http://www.beckwithtuckpointing.com/gauged-brickwork.htm
You see in their What We Do and the alternating pics, the contrast between the Mr Blobby job that is fine for a rustic cottage, and their finished work, which is what you're seeking.

You were wise to do a test panel.
It's not unuseful, it has served as an example of what you don't want.
Now all you need is someone who can do what you do want.
They will also know how to reconcile the variation in joint sizes.** A quarter to three-eighth is quite a difference.
Also, a firm with a track record will more readily win over the CO. Whose reluctance is better understandable now we have seen what the average builder regards as suitable pointing.

I admire your stamina.

Ivor

** which is interesting as it suggests different stages of build. The wooden cornice.... mmm... is it your understanding that the Georgian house was built as a piece, or do you think there was an earlier core? Apologies if you've covered this elsewhere.

 

[Gareth Hughes]

Except that what we have here isn't actually tuck pointing, but just fine joints (there's no sign of coloured mortar being used except in later patches, or of very thin lines of lime putty being, or having been, inserted into the joints).
I must admit I'm at a bit of a loss as to how the trial patch has ended up with such thick pointing, since removing the existing pointing doesn't appear to have reduced the size of the bricks, thus enlarging the joints (as use of an angle grinder can cause).
I tend to advise against repointing unless the existing pointing is actually doing harm, precisely because it often seems to lead to such a significant change in the building's appearance.

 

[plasticpigeon]

Pointing is tricky. I've done quite a lot now and my efforts are yielding acceptable results. If the pointing is truly flush it does end up looking a bit like that pictured. I think the smearing over the brick faces exacerbates the wide joints a bit too. I have found that rubbing the mortar back to just behind the face of the brick with the end grain of a piece of wood or similar when the mortar is just starting to go off vastly improves the appearance. Another alternative which I can see on some sheltered bits of my house is flush pointing with ruled joints. This is where a tool has been used to cut a straight line into the mortar at the top and bottom of the joint to give an even appearance and make the mortar joint look a bit thinner. Obviously if the bricks are quite even this can be pretty much on the intersection between mortar and brick exposing the arris a little. In the case of the bricks above, I think the mortar is also very light coloured, and a nicer look would be achieved with a darker mortar.

 

[overlander matt]

My feeling is the first attempt was a rather clumsy one by the builder who thought flush really was the best way to go when in reality this resulted in a wider joint when the brick edges are poorly defined. It's a shame because there was a lot of discussion leading up to the work starting about the importance of the pointing. The section has now been cleaned up a bit and another section pointed with greater attention to coming just short of flush to prevent exaggerating the joints. The finish appears neater but ultimately the gaps are wider at top than further down where the work is much finer. There's not much anyone can really do about this aesthetically. I take the point about using specialists for the work down lower in future.

The brick work in the top section has suffered a fair amount of damage from water leaking out of the lead gulley running around the top of the house. We have made good progress with repairs to the lead work and the wooden cornice. We've replaced around 100 bricks too - many simply removing previous repair jobs which seem to have been carried out with any old bricks the builder could find. I admit our bricks are not a perfect colour match given the black staining the house has suffered over time but they are the right size. It's amazing what was considered an acceptable repair in the past. It looks better now but this section will need repointing soon and obviously this must be in lime. We looked at colour matching the lime, settling on an Anglian Lime mix that didn't look too far off an old section of lime found inside the house. The reality is that new lime always looks a bit bright compared to cement mortar and it will need a few years to weather.

I am keen to get as much use out of the scaffold as possible. If I can get the go-ahead to repoint the whole front that would be great but if not then it will just have to be the top section for now.

Thanks again for the comments. It's useful to get some other opinions.

As for the historical development of the house Ivor, I have no idea when certain features were added.

Matt

 

[malcolm]

For the pointing the trick is to let the lime dry for an hour or two, tap it with a stiff brush to compact it a little, then use the brush in a side to side motion to remove the lime from the bricks. You get a feel for timing by experimentation. That way you can have flush pointing that is as thin as possible without any smearing on the bricks like the first photo. Brickies used to cement won't be familiar with the masonry brush so will need a bit of a pointer.

 

[88v8]

For the pointing the trick is to let the lime dry for an hour or two, tap it with a stiff brush to compact it a little, then use the brush in a side to side motion to remove the lime from the bricks. You get a feel for timing by experimentation. That way you can have flush pointing that is as thin as possible without any smearing on the bricks like the first photo. Brickies used to cement won't be familiar with the masonry brush so will need a bit of a pointer.

Interesting. I've seen that done with coursed rubble, and rusticated work, never with gauged brick. Does it leave a decent finish on the mortar face?
As I mentioned, I've used hessian - old potato sack - for rubbing back the mortar.
The timing is quite crucial, and some limes go off faster than others. Too soon and it will smear, too late and the joints end up overly fat.

Ivor

 

[88v8]

As for the historical development of the house Ivor, I have no idea when certain features were added.

I was just thinking that the wood cornice may have been adopted as a means of giving a formal Georgian profile to the higgledy roofscape of an older house.

Ivor

 

[malcolm]

Interesting. I've seen that done with coursed rubble, and rusticated work, never with gauged brick. Does it leave a decent finish on the mortar face?
As I mentioned, I've used hessian - old potato sack - for rubbing back the mortar.
The timing is quite crucial, and some limes go off faster than others. Too soon and it will smear, too late and the joints end up overly fat.

Ivor

The brush is a fairly common technique when you have some larger bits of aggregate in the mic and want to expose it for a bit of texture. It cleans the edges of the bricks without recessing the pointing but will leave a textured finish.