Sealant, vertical gap between widths of brickwork?

[pe2dave]

Any idea what it's called please? 25 yo wall, sealant is coming out.
10? foot of brickwork then (expansion gap?) filled with some sort of brown sealant.

 

[Fitzroy]

Sounds like burnt sand mastic? Although why you need it between brickwork seems odd, as bricks don't (shoudn't) expand/move.

 

[Bingy man]

I’d remove the old sealant and replace with a quality exterior sealant but not silicone. I see these ( expansion) gaps everywhere there are long sections of brickwork. I too wondered about how a brick wall can expand and contract but I’m guessing it’s just to keep water out and of course if water got into the joint it’s going to cause issues especially in winter when it can freeze and err ? expand…

 

[pe2dave]

Sounds like burnt sand mastic? Although why you need it between brickwork seems odd, as bricks don't (shoudn't) expand/move.

Thanks @Fitzroy New one on me 'burnt sand'!
I'll look it up.

 

[pe2dave]

I’d remove the old sealant and replace with a quality exterior sealant but not silicone. I see these ( expansion) gaps everywhere there are long sections of brickwork. I too wondered about how a brick wall can expand and contract but I’m guessing it’s just to keep water out and of course if water got into the joint it’s going to cause issues especially in winter when it can freeze and err ? expand…

Any idea of a trade name please? Exterior sealant could bring up almost anything?

 

[ChaiLatte]

Any idea of a trade name please?

Geocel 201, Everflex 115 or equvalent. Both come in various colours.

https://www.sealantsonline.co.uk/Products/Mastic-joint-sealants-online

 

[pe2dave]

Geocel 201, Everflex 115 or equvalent. Both come in various colours.

https://www.sealantsonline.co.uk/Products/Mastic-joint-sealants-online

Silicon, acrylic, still lots of choice?
Any advice on which one please?
These are all 'building' sealants?

 

[Blackswanwood]

Silicon, acrylic, still lots of choice?
Any advice on which one please?
These are all 'building' sealants?

https://www.sealantsandtoolsdirect....l-based-traditional-building-mastic-4-colours

 

[pe2dave]

From reviews, this seems appropriate.

 

[Doug71]

I'm no expert but from what I've seen they often just use a generic builders silicone something like

https://www.sealantsonline.co.uk/ProductGrp/Everbuild-everflex-450-builders-silicone-sealant
You also see foam roll but that might not work for you

https://www.travisperkins.co.uk/exp...ansion-joint-roll-10mm-x-100mm-x-10m/p/837980
With regards to burnt sand mastic I've used it a bit for sealing around windows etc but never really got on with it, trowel mastic is the modern take on it and I find easier to work with.

https://diyrefurb.co.uk/product/103-trowel-mastic/

 

[highwood122]

Sounds like burnt sand mastic? Although why you need it between brickwork seems odd, as bricks don't (shoudn't) expand/move.

all brickwork expands/contracts slightly.expansion joints are there to stop cracks elswhere in the wall

 

[Bingy man]

Any idea of a trade name please? Exterior sealant could bring up almost anything?

As long as it’s a mastic based sealant tbh there are 100,s , look at obviously water proof, resistant to u v , flexible, will not shrink or crack . Most of the above suggestions will be fine . Depending how wide the gap is try to get a deep fill. If you not too good with sealing this type of gap or just to make a super neat job then mask off either side and the job is done . Unlike silicone mastic /exterior frame type sealants will slowly cure .

 

[Lons]

Of course brickwork expands/moves and if you do some research you'll find details on how and where expansion joints should be provided. New bricks especially can continue to expand for a long time. Expansion joints are often not noticed at first glance. As far as replacing the sealant there isn't much to choose between them, as long as it's flexible, doesn't shrink and stays stuck it will be fine, it's only purpose is to keep water out. That said, bricks are porous and it varies depending on density.

My neighbour had a low garden wall built a few years ago, chose the hardest bricks available, the run along the front is probably 30 metres, no expansion joint and the top rows moved more than 25mm in 18 months, was a right mess.

 

[Doug71]

I was working on a new build recently and noticed there was an expansion joint in the middle of both end internal block walls, it was about a 10mm gap running from the ground floor right up to the top of the gables in the attic, it looked like the house had a big crack down the middle of it. There was nothing in the external brickwork, just the internal blocks.

 

[ChaiLatte]

You also see foam roll but that might not work for you

The foam is used as a backer to the mastic as you do not fill the brick full depth with gunge.

As the TP product, you buy it with a tear off strip so you build it into the wall and in so doing it stops the mortar bridging the gap. Then, when ready to fill the joint, you tear off the 15mm strip and squeeze your sealant in.

If the gap is too deep and does not have a soft filler material in it already, the circular foam backer rod is easier to poke in than anything with square edges.

 

[Housey210]

Any idea what it's called please? 25 yo wall, sealant is coming out.
10? foot of brickwork then (expansion gap?) filled with some sort of brown sealant.

plenty of vids on youtube- "How to Seal An External Brickwork Expansion Joint" Known pu mastic to be used. NHBC, building control at council or tech college bricky department might be worth a call.

 

[Valeboy]

Any idea what it's called please? 25 yo wall, sealant is coming out.
10? foot of brickwork then (expansion gap?) filled with some sort of brown sealant.

Just rake out the old rubbish and push this stuff in, easy, never changes... https://www.wrmeadows.com/x-foam-flexible-lightweight-concrete-expansion-joint-filler/ Or UK equivalent product, can't think of the one I used to use but I'm sure you'll track it down. You can push this in, wait for it to expand then cut it flush with a craft knife. Compriband TP600 Expanding Weatherseal Strip – Specialist Construction Supplies

 

[pgrbff]

Thanks @Fitzroy New one on me 'burnt sand'!
I'll look it up.

Burnt sand mastic is a mix of burnt sand and linseed oil. Its used around windows and not recently. I doubt it is what you have. Picture would help.

 

[MikeJhn]

The foam backing rods are there to ensure the expansion material is not as deep as it is wide, ideal width to depth ratio is about 4:1 to allow movement, expansion gaps in brickwork should at every 4.5M approximately, difference between Acrylic and Silicone is that you can paint Acrylic, Silicone is self coloured, but longer lasting.

 

[pe2dave]

The foam backing rods are there to ensure the expansion material is not as deep as it is wide, ideal width to depth ratio is about 4:1 to allow movement, expansion gaps in brickwork should at every 4.5M approximately, difference between Acrylic and Silicone is that you can paint Acrylic, Silicone is self coloured, but longer lasting.

Thanks @MikeJhn There's already some brown filler in the gaps (not well done) so I doubt I could fit the foam strips in.
I've ordered some filler and I'll try to hack out the existing as best I can.
After 60m of repointing, I think the joints warrant looking good