Howard-
That 'Decorators Exterior' stuff will shrink by 10-15% as it dries.
It is water based and must lose the moisture to fully cure.
It also has only limited movement accomodation.
You are likely to find it has delaminated from one substrate or the other,
(depending upon which it sticks to worse), after a Summer.
Treat yourself, and the property, to something from the Soudal Fix All range.
The High Tack Adhesive & Sealant is available in white from Toolstation. -
Whatever you use, you will need to consider the relative porosity (as well as movement / contraction / shrinkage) versus the soft stone and softer bricks that you are butting against (you can already see some spalling where the pointing is cement and has exacerbated water damage on the brick face).
Modern stuff is great, and works great with modern bricks & cement - not so much on turn of the century solid walls with lime mortar.
You are reading a single comment by @Howard and its replies.
Click here to read the full conversation.
mespilus
NotThamesWater
The olde fashioned way is burnt sand mastic, which expands & contracts with the stone mullions and wooden sash.
Or just cement render the lot, and sell before the inevitable water damage.