sealing wood to brick

I want to attach a wooden frame to a brick wall and seal it air tight. The brick surface is uneven and there are the mortar grooves so there are gaps up to 10mm to fill.The wood is 35mm wide.

I want the filler to be fairly dense to keep out noise so I'm wary of silicone gap fillers. Window putty sounds more like it but I worry about it drying and breaking the seal. I've thought of using plasticine which is very similar but supposed to be non-drying. Then I'd need a way to seal the plasticine and paint over it.

How does using plasticine sound? Do I worry too much?


Read and reply to the full thread at RenovateForum.com....