Sash window frame seal

[Madrab]

Hi there,

Just looking for any recommendattions for the best way to seal old sash windows to red sandstone. I have sash windows and all around the frame it had been sealed by what looks like a red type of mortar. This is now crumbling and cracking and missing in various places. I aim to remove all of this and replace to ensure wind and water tightness.
Is their a modern equivalent that I can use? I assume that whatever I use would need to be flexible given the fact they are oak frames, that expand and contract depending on the conditions, I assume this is why the original mortar is now failing.
The job is made doubly difficult as there is quite a large void behind the frame and will take a huge amount of material to fill. I have been pulling out newspaper from the 50's that was originally stuffed in behind the frame to support the mortar (interesting reading )
I hate to use the words 'expanding foam' but would this be suitable to initially fill the void in this case? I have also seen Soudal's brown exterior frame sealant, would this be a suitable sealing alternative on top of the foam?

Any suggestions would be greatly appreciated...

Many thanks

Rob

 

[Symptoms]

Mad - consider 'block pointing' with sand/cement mortar ... obtain a red sand for your mix to get a match for your stone. Block pointing is the 'correct' way to do this and obviously fits with any heritage issues regarding old buildings.

Mastic and/or expanding foam would work but ... yuk, IMO.

 

[joe-90]

If you were pulling paper out from the 50s - then that's a pretty long lived job. Sixty years and you' re complaining?

 

[Harbourwoodwork]

The stuff you are pulling is probably sand mastic ,linseed oil sand and colour red ochre

 

[Madrab]

If you were pulling paper out from the 50s - then that's a pretty long lived job. Sixty years and you' re complaining?

Lol...not complaining Joe, just wondered if there was an easier modern equivalent

Mad - consider 'block pointing' with sand/cement mortar ... obtain a red sand for your mix to get a match for your stone. Block pointing is the 'correct' way to do this and obviously fits with any heritage issues regarding old buildings.

Thanks S, when you say block pointing how do you mean? Would a mortar mix be flexible enuf given the natural movement of the wood frames/stone?
I still have the issue with the void behind the frame as anything I would try to fill it with would just fall through the gap and into the space behind the stonework ergo the expanding foam idea rather that several scrunched up copies of the Sunday Sport

The stuff you are pulling is probably sand mastic ,linseed oil sand and colour red ochre

Seems that may be what it is Harbour, spotted stuff called Burnt Sand Mastic - Burnt red sand, with oil and driers supplied as a 2 pack system, seems to be really involved with mixing and proving for 2 hrs prior to application and can be tricky if mix not correct though

The other stuff I've just spotted seems to be called poly sulphide mastic that is the modern equivalent applied with a gun, anyone used that before?

 

[Harbourwoodwork]

sand and cement is a 2 pack,polysulphide is great stuff in the right place it could so easly end in tears ,foam the back of the frame,but brace with wedges round the sash foam is very powerfull and can distort the frame trapping the sashes !!!trim of and point up as Sympton said, you could add lime

 

[Harbourwoodwork]

sand and cement is a 2 pack,polysulphide is great stuff in the right place it could so easly end in tears ,foam the back of the frame,but brace with wedges round the sash foam is very powerfull and can distort the frame trapping the sashes !!!trim of and point up as Sympton said you could add lime