Should I paint before fitting windows

[garethharvey]

Struggling a little with this one, I am replacing our glasshouse, the last one has pretty much rotten and all the paint failed. This time I am using Western Red Cedar which is also more substantial on the size.

Should I pain the units prior to fitting or should I fit then paint. I am thinking the end grain of the units will possibly rot. Alternatively, is there something I should put on the eng grain? I am using linseed oil paint

 

[Jacob]

Paint after, not before.
Everything out of sight should be paint free. Especially bottom edges - if not then paint seals moisture in and you can end up with bottom rails getting waterlogged and rotting.
On the other hand linseed oil paints are more breathable than any modern paints so the advice to prime first before installation, with linseed oil only , is probably good. But definitely not paint first - this gives you a handling problem amongst other things; waiting for it to dry and would all need touching up etc.

 

[Phil Pascoe]

I've not known any windows I've ever made or fitted to rot, and I've always soaked them in a good preservative, primed and undercoated all round before fitting, then undercoated and glossed after fitting. If the weather turns vile and you don't get back to them for months you don't have too much to worry about. How is the moisture to get in if they are painted all round and maintained?
I've taken a whole load of rotten ones out that haven't been painted all round.

 

[Jacob]

..... How is the moisture to get in if they are painted all round and maintained?.....

They'd have to be perfectly maintained to keep moisture out. But sooner or later paint fails, especially at joints, putty lines etc and water gets in. I've taken out modern frames which have been literally waterlogged along the bottoms - painted underneath and not helped by being set on mortar beds instead of having an air gap.
Whereas all the trad stuff I've ever removed, sometimes 100 years old, shows no sign of paint anywhere unnecessary and out of sight.

 

[Phil Pascoe]

And all the trad stuff I've removed has been rotten. I agree with the point about their sitting in a bed of mortar, though.

 

[garethharvey]

Thanks Guys, my main concern in the mitres on the cill, there are 8 in total. Would I seal the cill with silicone or anything when fitting?

 

[Beau]

I've not known any windows I've ever made or fitted to rot, and I've always soaked them in a good preservative,

Not made loads of windows and most have been stained not painted but would definitely recommend a good soaking in clear wood preserver before painting.

 

[Phil Pascoe]

Be careful putting silicone anywhere that has to be painted - better to find another flexible filler that can be overpainted.

 

[Phil Pascoe]

I've not known any windows I've ever made or fitted to rot, and I've always soaked them in a good preservative,

Not made loads of windows and most have been stained not painted but would definitely recommend a good soaking in clear wood preserver.

I should actually have said I soak the parts before assembly. The joints then are in with a chance. I regularly pass a garden gate I made nearly 25 years ago that's still immaculate - it's made of (commercially) untreated whitewood.

 

[Beau]

I've not known any windows I've ever made or fitted to rot, and I've always soaked them in a good preservative,

Not made loads of windows and most have been stained not painted but would definitely recommend a good soaking in clear wood preserver.

I should actually have said I soak the parts before assembly. The joints then are in with a chance. I regularly pass a garden gate I made nearly 25 years ago that's still immaculate - it's made of (commercially) untreated whitewood.

I have not gone that far but have put the finished windows and frame upright in a tray of preserver so it can soak deep into the wood. Does soaking it before glueing not make the joints expand and mess up the joint fit?

 

[Phil Pascoe]

It seems to make little difference. I soaked the parts in that instance for about two weeks then allowed them to dry for about the same before assembly - it wasn't noticeable then that anything had been done to them at all. I have done everything that way ever since.

 

[ColeyS1]

I always send stuff out with 2 coats of aluminium primer before it leaves the workshop. Everything gets two coats before any glass gets fitted. - Thats using oil based paints though. Perhaps it's different for linseed paint.
Coley

Sent from my SM-G900F using Tapatalk

 

[RobinBHM]

We paint on end grain sealer to any cill ends, end of stiles on doors etc.

Cills have their edges radiuses with an approx 3mm rad on top and front edge. the mitre ends are sealed with end grain sealer. The cills are then joined with MS polymer sealant which is also used in the V formed by the radiused edges.

Generally it is good practise to avoid a sharp 90 degree sawn edge at joints or any other edge. If for example a tightly jointed cill is painted over, if the cill expands and ocntracts then it could crack the paint at the joint. A 3mm radius on all edges mean paint flows around the radius and the film thickness is maintained. If unseen faces are not painted then the same applies

 

[Phil Pascoe]

I always send stuff out with 2 coats of aluminium primer before it leaves the workshop. Everything gets two coats before any glass gets fitted. - Thats using oil based paints though. Perhaps it's different for linseed paint.
Coley

Sent from my SM-G900F using Tapatalk

I worked a while ago with a very good joiner who wouldn't price for jobs that weren't to be coated in preservative, primed and white undercoated. He'd had too many complaints about his work rotting, shrinking, expanding ... when people had fitted it for a few years without getting around to painting it.

 

[Jacob]

I always send stuff out with 2 coats of aluminium primer before it leaves the workshop. Everything gets two coats before any glass gets fitted. - Thats using oil based paints though. Perhaps it's different for linseed paint.
Coley

Sent from my SM-G900F using Tapatalk

I worked a while ago with a very good joiner who wouldn't price for jobs that weren't to be coated in preservative, primed and white undercoated. He'd had too many complaints about his work rotting, shrinking, expanding ... when people had fitted it for a few years without getting around to painting it.

Yep you need belt and braces with modern paints - plus preservatives, plus very regular maintenance. They are all cr*p. Linseed oil paints utterly superior "Allback" and other brands

 

[Phil Pascoe]

I doubt linseed paints would have been any better if they weren't used.

 

[Jacob]

I doubt linseed paints would have been any better if they weren't used.

er - what?

Oh I see what you mean - if they weren't used for regular maintenance. Actually if used from the beginning they are amazingly durable even if not maintained. Won't last forever but will certainly do better than any modern paints.

 

[RossJarvis]

Having done a fair amount of re-painting over the past couple or three years, the main reason exterior wood rots out is due to lack of maintenance and poor initial preparation. Poor design is also a factor. I'm not convinced that linseed oil paint is substantially better than modern paint, but I wouldn't be surprised if it was.

As some have said, treating the wood before or after assembly will help, but I don't think this was done 100 years ago and some of those windows are still sound and good redwood is the same as it was then. Any exposed end grain should be sealed. Only the exposed areas need painting as proper construction should keep the rest dry. There shouldn't be any sharp edges (arrises) either., 3mm radius is the current spec but in the past all arrises would be relieved and not left sharp which may have only been a mm or so. Whatever paint to be applied should be selected for it's longevity and will probably be a system which should be followed to the letter. After that the paint should be checked every year, particularly at joints and recoated regularly, 3 years is the standard time for a re-coat even for most modern paints and few if any can last beyond 8. I usually hear "it was only done 5-8-10 years ago"

When I were a lad every year all the neighbours would be out checking or doing the painting over the summer, nowadays people generally think of repainting when the old paint is falling off, which is after it's too late. I'm currently repainting the woodwork on my brother's house and as expected found the exterior doors had not been painted on the bottom. Most "Professional" painters these days generally don't know much about painting so I doubt whether much new woodwork since 1980 has been painted well and I dare say it's similar for a lot of modern joinery construction.

 

[AndyT]

Not sure if it's relevant with modern waterproof glues, but plenty of old books up to about WW2 say that for exterior work you should paint all the joint faces before assembly.

 

[garethharvey]

Thanks, I know where I am going with this now, will be coating all the cills with wood preserver, paining the Cill end grain with end grain treatment.

Will assemble the glasshouse before painting, will leave the bottom of the Cill unpainted for water to escape. I have made all the mortice and tennon joints all the way through so water can also escape.

Primer for linseed oil paint is just pure linseed oil. Am I right in thinking this can all be painted with the raw oil prior to assembly?