When to repaint sash windows...

[overlander matt]

We repaired our sash windows 6 years ago - all the usual rot to the sills and lower sashes etc. We used the Repaircare products for filling and reglazing then finished off with 3 coats of Bedec MSP. I should add that we replaced the sills with Accoya as part of this project.

Fast forward 6 years and the finish is looking a bit tired. The paint on the sills is looking thin and lichen-covered in places, the parting beads have not held up too well, generally it's just looking a bit shabby.



I had planned to repaint the front windows this summer but the garden wall project has overrun and I'm looking for a way out! I still have some more pointing to do on a wall close by and the dust is going to spoil a newly painted finish.

The question is what to do? How often do you repaint windows and is this a full repaint or just what is needed? I'm inclined to do some maintenance ahead of autumn, painting sills and other areas where the paint looks thin.

The windows had a wooden beading fitted with an exterior caulk seal against the brickwork. I'm considering changing this for a more traditional caulk. I've never used burned sand mastic but this could be the right way to go. I also avoided the stone sills last time, hoping the old paint would gradually wear off. I like the idea of bare stone sills...

It would be great to hear how others approach their window maintenance. Thanks!

 

[fernicarry]

Hi Matt, I'm glad its not just me. Sills and parting beads don't seem to last any length of time here. I'm having a lot more success on the longevity front with Demidekk than with MSP though. The more sheltered windows at the back here did last 12 years with MSP but are now looking well overdue for a repaint. The exposed ones at the front looked pretty shabby after 3 or 4 years so I have a rolling program to tart up with Demidekk (which I'm reminded hasn't rolled very far this summer...).

I just repaint the most weathered parts, cill, part way up the pulley stiles and parting bead. Since I can't get a particularly close colour match to Bedec Old White with Demidekk I also give them a couple of quick coats of MSP afterwards to lessen the contrast. This might negate Demidekk's supposed ability to resist algae growth on the surface but so far the repainted sills have stayed pretty clean. I'm redoing the roofline woodwork at the moment and areas that I did less than 5 years ago with MSP are completely black! The joys of overlooking a sea loch...

I think part of the problem with the parting beads is the primer they are supplied in. That fails and takes the top coat with it. Not helped in that the end grain is perpetually standing in a puddle so needs to be well sealed. I try to them back to bare wood so I can give them the full Jotun system.

 

[overlander matt]

Thanks Alan. It's helpful to know how others are getting on with their windows. You certainly have a more exposed spot than we do, so if Demidekk works for you it should work here...

Having gone back to bare wood 5-6 years ago, I'm most likely only going to do the bare essentials this autumn. Probably a bit more MSP.

I'm wondering whether you could cover old MSP with Demidekk in a future repaint? I also have a lot of painting at roof level but I never want to have to strip the paint from up there...



Have you tried burnt mastik on your windows? I want to replace the modern caulk used here if it's easy enough to use.

Another interesting project could be reinstatement of the external shutters that were removed in the 1980s but there's plenty to do before that ever happens!

 

[fernicarry]

whether you could cover old MSP with Demidekk in a future repaint

Should be fine, subject to the usual sound surface caveats. At roof level I have a mixture of existing and new wood so the existing gets a thorough prep and many coats of Demidekk. The new wood is primed with Visir and edges and back painted with Ultimate (which is now called Cleantech) before it goes up. Trying to give it all the best chance of survival.

Have you tried burnt mastik on your windows

I tried a while back and it wasn't really a success but I'll be having another go shortly. I put a bead of 215LM on the junction first as an extra barrier so I'm viewing the burnt sand as more cosmetic than functional.

 

[overlander matt]

Thanks Alan. Interesting to hear about the burnt sand mastic. Was it messy to use? It should be more cosmetic than the sealant used previously.

Not really looking forward to the painting but needs to be done...

 

[fernicarry]

Was it messy to use?

Yeah, a bit. I set myself up for failure by trying to do along the top of a window first and ended up wearing and treading in most of it... Gave up in disgust. But the postie has just left me a fresh bucket of it so I guess I should psych myself up to try again.