Refinishing old wooden windows

[coulson84]

We recently moved in to an old house which has some leaded glass windows in wooden frames. I've stripped the old frames down which involved removing what looked like mortar that was filling the gap between the frame and the outer wall.

Now I'm ready to refinish them but I'm not certain what to use to fill the gap between? Should I just use mortar again or is there are better alternative available these days? Should I just use some expanding foam and seal over the top of it?

Here's a couple of pictures to illustrate.
Thanks

 

[DAZB]

The windows will have been sealed with trowel mastic and perfectly good to be resealed with it again. Use the red version to match the bricks.

Everbuild Trowel Mastic Stone

Sika Trowel Mastic Stone is a premium oil-based mastic for perimeter pointing around wood and metal window and doorframes

www.buildingmaterials.co.uk

 

[lostinthelight]

Or if a traditional building theres :

Traditional Burnt Sand Mastic Archives - masons mortar

Used to form joints, you can ensure our high quality product is durable and flexible for its purpose. It adheres to most surfaces.

masonsmortar.co.uk

 

[Dereekoo]

Whats the white line down the side of the brickwork, did the window have a front bead and if so are you putting it back

 

[coulson84]

The white line is just some left over paint I haven't scraped off yet. The previous owners had painted the frames and all the mastic that was there previously with white gloss.

I've filled the gaps now. Thanks for everyone's input. I can safely report that tile mastic is a real pain to work with

 

[Notch7]

Or if a traditional building theres :

Traditional Burnt Sand Mastic Archives - masons mortar

Used to form joints, you can ensure our high quality product is durable and flexible for its purpose. It adheres to most surfaces.

masonsmortar.co.uk

Funnily enough I was pointing up some box sash windows with burnt sand and linseed oil this week - it takes a long time to harden