Which kind of mastic?

[Agile]

I went yesterday to assess a situation where water leaking into a flat had tripped the kitchen ring main and the tenant did not want to reset it.
The landlady had worked out that the gutter had been leaking and water somehow entered the property. She got the gutter cleaned and it is no longer overflowing. She had the roof replaced about six months ago and the disturbance had left a lot of loose grit which had washed down into the gutter with the recent high rains.

I discovered that a 50mm waste pipe leaving the upstairs flat was quite loose where it went through the wall and the overflowing gutter had caused water to enter the house around this loose pipe and that had run down the wall inside and flooded a switched fused spur.

So to remedy this problem I want to chip away a little brick and mortar around the pipe and fill the space with a suitable mastic.

Can anyone suggest the best mastic to use, ideally one sold by Toolstation, as that is convenient. Obviously it needs to stick well to both brickwork and plastic pipe!

 

[^woody^]

Any silicone or polymer/hybrid. Not acrylic.

 

[Agile]

OK thanks.

I had a look at what Toolstation were selling and decided to buy their Ever Build External Frame Sealant as most of its stated capabilities seemed suitable and the brown colour was less noticeable.

Although it does say that it is acrylic which you advised against.

Anyway we will see how effective it will be. Since the blocked gutter has now been cleaned the masses of water cascading down the wall will have ceased.

 

[^woody^]

"Frame sealant" tends to be acrylic, which skins and cracks.

 

[Wayners]

Polymer like CT1 or OB1.
Everbuild one is a OK at around £7.
Cheaper ones either don't give and more for sticking or a little thin.
Will stick to wet or damp surfaces unlike silicone.