Please stop me if I'm about to do something really stoopid...

[PotatoSoup]

Thank you so much for reading this - please help! The DPC around my bathroom window is shoddy and there's a big gap between the metal lintel and the aerated block. I'm planning to stick Gorrila waterproof patch and seal tape to the window frame and dpc on the sides of the frame and the bottom. Then stick the tape to the metal lintel and the frame. Is that insanity or ok? Please someone tell me?

 

[PotatoSoup]

I'm obviously going to finish cleaning the frame and dpc with Wonder Wipes and get all the silicone off first

 

[Deluks]

Expanding foam is the way to go, don't get it everywhere though, trim back when it's cured.

You could then bump out those reveals with some insulated board.
Either plasterboard laminate or foam tilebacker board.

Does it leak or let any water in during heavy wind and rain?

If so, then you need to fix that from the outside.

 

[PotatoSoup]

Hiya, thank you for your quick response!! Trying to avoid foam because I'm neurotic and don't like the fact it suggests on the label that it's a possible cancer risk

 

[PotatoSoup]

...No leaks at all.

My concern is that I'll somehow cause a damp problem with sticking the tape to the frame and dpc (because I don't know what I don't know).

The draft coming in around the window was quite noticeable so stuck extra DPC in where there were gaps, securing it to the existing dpc and the window frame and then did a surround of the tape.

Plan is to now put 2 layers of insulated knauf pb on the bottom and 1 layer on the sides and top, dot and dabbed on.

Then a plastic window cill

 

[PotatoSoup]

It's not pretty but it is sealed!

 

[oldbutnotdead]

Sticking tape etc across a gap will stop the draught but it'll still be a cold surface- prone to condensation in an area like that.
Exp foam can be vile stuff (especially using the throwaway trigger/tube instead of a real gun) but it will give you proper insulation so the inner face will be warmer.
Lots of things are possible cancer risks.....if you're worried about making a mess just mask off the work area with pvc tape and lots of polythene.

 

[Wayners]

£15 metal foam gun from B&Q
In building section not decorating.
Masking all over window.
Can't see any other way.

Im with you on the chemical's though.
Unavoidable exposure these days but you can get some PPE for application.

 

[johnny2007]

One application of expanding foam won't give you cancer.
God knows how many times we've all been exposed to asbestos fibres in the good old days and not all of us get cancer, only the ones who had extensive exposure to it.

 

[Koolpc]

As above, go with the foam. A much more superior choice.

You wont be eating the stuff so dont worry!

Mask off first around the window.