Weekly update 27.09.2015

The sash window in the dining room was in need of some attention.  It was obvious that there was a bit of rot in the sill where one or more TV cables had been run in from the outside.

The full extent of the rot was not clear without a bit of "digging".  The surrounding paint just flaked away when touched, revealing some rather soft and crumbly wood.  I pulled out the old co-axial cable and the two plastic tubes and this dislodged more rotten wood.



The more I scraped, the more rotten timber was revealed.  My hopes of filling the damaged area just using plastic filler quickly diminished!

Cutting into the sill further along revealed that, although the surface looked fairly sound, the core was soft.  I therefore decided to cut the whole sill back to sound timber, using the sonicrafter tool.

Once again, Screwfix came to the rescue with this product from Ronseal - does exactly what it says on the tin!  That's to say that you brush it onto rotten timber, it soaks deep into the soft fibres, then sets rock hard to provide a firm surface from which to repair.

...so the whole length of the sill was treated.  The mortar bed below the sill was sandy and crumbly so I scraped this out and backfilled with fresh mortar.

A new length of redwood was sourced from Gibbs and Dandy.  I had them plane it down to 60mm x 70mm for me.  I then planed a chamfer on the top edge to allow the rain to run off and routed a drip groove on the underside to prevent water from running back underneath.

The knots were treated to prevent the resin from leaking and attacking the paint finish.

The old and new frame timbers were drilled to accept lengths of 12mm diameter dowel.  These will be bonded using waterproof PVA and provide a strong interface between the two components.

A fresh bed of mortar was applied to the bricks, adhesive applied to the dowels, a thick bead of silicone sealant applied to the mating surfaces and the whole lot clamped together.  The mortar was then tidied up.  At this stage, I decided it was better for the mortar to come right to the front edge, rendering the drip groove somewhat redundant.

With the main timberwork done, I then turned my attention to the details.  A piece of the outer frame had also been removed due to rot.  I contoured a fresh piece of timber, then glued and tacked it in place.

Once set, the join was filled using high performance, two part wood filler...

...then sanded back to a smooth finish.