How do I repair exterior

[JamieConnell90]

Hi I was out in the back garden yesterday and I noticed that the sealant join between my.house and the neighbours house is falling apart and exposing the cavity between the two houses.

I was wondering what would be the best way to to fix this before the winter properly sets in.

I have attached pictures too and anyhelp would be great

 

[Mrs Ten Names]

Is that cement of some kind of mastic filler?

You say "falling apart". Do you really mean a differential movement between the buildings?

 

[JamieConnell90]

It's some kind if mastic filler and no I mean it is falling apart and coming off completelyin sections exposing the cavity. Movement between the buildings shouldn't cause it to be that bad would it? The buildings are nearly 30 years old aswell

 

[Mrs Ten Names]

It's some kind if mastic filler

Then it needs replacing. Due to the limited lifespan, it's sensible to pull it all out and replace it all.
If there's no differential movement between the buildings and assuming it's about 25 - 30mm wide, i don't see why mastic filler was used.
Pointing up with mortar would offer a longer lifespan as a filler. But mortar is not a flexible filler.

Movement between the buildings shouldn't cause it to be that bad would it? The buildings are nearly 30 years old aswell

Is there any differential movement between the buildings?
If there is, it needs to be a flexible filler, like mastic.

Another alternative would be to fit some kind of cover to the cavity.
There may be a plastic glazing type of cover, but in lengths more suited to soffits, etc.. You'd need to peruse the availability at your nearest plastic supplier.

A wooden cover might suffice, if it's a hard wood, or a well protected soft wood.

 

[JamieConnell90]

Thank you there is also some kind of foam under the mastic, I am assuming that will need replaced aswell but not sure what kind of foam it is

 

[Mrs Ten Names]

Thank you there is also some kind of foam under the mastic, I am assuming that will need replaced aswell but not sure what kind of foam it is

Expanding foam.
If you've never used it before, it'll be messy.
But the foam may not need replacing, unless it's not possible to remove the disintegrating mastic without affecting the foam
Simply fill any gaps in the foam before applying the mastic.

The foam can be trimmed with a knife after it's cured.
You could fill any gaps in the foam, then cap it as suggested earlier.
If you were going to do that, I'd embed some bits of wood in the foam for fixing the capping.

 

[cdbe]

The "expansion joint mastic" needs replacing - that's all. The "expansion joint foam" is not expanding foam and can be left in place unless it's damaged.

 

[JamieConnell90]

It's not expanding foam but it is damaged aswell, would it be easier to pull out with the mastic and fill with expanding foam, trim, then apply the new mastic? Sorry for the constant questions I just want to make sure I am doing it properly.

 

[Mrs Ten Names]

Replace the expansion joint foam, and the expansion joint mastic, as per cdbe's post.

I would still consider capping it, after the expansion joint foam has been replaced.
Make sure you only fix the one side of any capping so that any expansion of the buildings does not rupture the capping.

 

[JamieConnell90]

Brilliant thank you

 

[stuart45]

Look for backer rod foam. You can get different thicknesses. It needs to be a reasonably tight fit to hold the sealant.