New replacement sash windows - which paint for which faces?

[Goldnet]

I’m in the process of painting new hardwood sash windows ready for the fitter. I’m using Dulux Trade Weathershield paint for exterior with Trade Eggshell for the inside finish. As I am also replacing front and back doors, where the manufacturer specified no water-based paint to the used, I’m using only solvent based primer, undercoat and top coat.

I’ve just completed undercoating all the window components, frames, lights, beading. I’m not entirely sure which surfaces require the exterior gloss. Obviously the outside face of the lights, the external beads and all but the inside face of the frame will be gloss. Are the top, bottom, sides and inside face of the lights then ok to finish in eggshell Or should the bottom edges of the lights, which may be exposed to weather be in gloss? What about the side edges?

Joiner specified 2 coats primer, 2 of undercoat. Do I assume 2 of topcoat too (with maybe one being sufficient for the eggshell inside?)?

 

[fernicarry]

By lights do you mean the sashes themselves i.e. the sliding parts with the glass in them? By "top, bottom, sides" do you mean the outer edges of the sashes?

Any part of the sash that slides against the frame should not be painted, so don't paint the 'sides' at all, not even primer. Similarly any part of the frame that isn't visible when the sash is closed, the inner faces of the pulley stiles (the sides of the frame), the inner faces of the outer linings etc. You should end up with a checked pattern on the pulley stiles, the bottom/inside part is bare as is the top/outside part. If you still have your old windows in place then refer to those.

I don't paint the top of the top sash as it shouldn't be exposed to weather. I've got 160 year old top sashes that have never seen paint on the top edge. Top of the bottom sash is an inside face.

Bottom edge of both sashes need painted. The bottom rails get the most weather so need particularly close attention. A good continuous coating from putty line down the front face and around the bottom. You need a slight overlap from the putty onto the glass to make a seal (not sure if this still holds when the glass is secured with a timber bead rather than putty, I imagine it must). Turn the sashes upside down to do this so that you can see what you are doing rather than trying to work upside down at an awkward angle. Be wary of the bottom sash sticking to the sill after assembly, this is the only place you will have two painted faces in contact with each other.

If you are painting the parting beads separately check that they still fit into the slot afterwards. The extra thickness of the paint might make assembly more of a challenge. Similarly the rebates where the pulleys go. Be prepared for your joiner to wreck your paint finish to get it all to go together...

Aren't the new sashes being supplied in primer? Its a good idea for the joiner to spray them with primer before fitting the glass.

So far as internal top coat is concerned, as many as you need to get the decorative finish you want. Unlikely one will be enough to cover the undercoat. Do pay particular attention to the top face of the bottom rail of the top sash (upward facing face where the latch is fixed) as condensation can run down the glass and pool there and as its not a very cosmetically visible surface it tends to get a cursory coating. Over time the water will soak in behind the glass and it'll rot from the inside out. Neglected sashes are usually black with mould here (at least mine were, maybe I'm just a mucky puppy....).

As for choice of paint system, what you've been steered towards, at least for the external part, is unlikely to be terribly well received on here. Is this for warranty purposes? How much do you think you can rely on the warranty 10 or 20 years down the line?

 

[Goldnet]

Hi and, first off, thank you so much for your speedy and comprehensive answer and advice.

Yes, “lights” was the term used by the joiner, it is the actual glazed sashes (he delivered them without glass and I had to get the beads and sashes to first undercoat when he collected them for glazing and returned them ready for second undercoat and topcoat. When I referred to top, bottom and sides, I was meaning the edges of the sashes, yes.

I ought also say that these windows are “modern” sashes in the sense that they use spring balances fitted into grooves in the frame, rather than pulleys and ropes. They are also glazed with a single dg pane in each sash, with the 3 ‘panes’ delineated by bars attached to the outside of the glass. There is an inserted brush seal along the centre where the sashes meet. There are inserted V seals where the sashes lie flat on the frame. There is no putty, the pane being siliconed in place and secured by angle beading except in the top side of the lower sash where it is left open. The joiner told me this is in any case hidden behind the outer sash so not visible, no exposed to water and is the way sashes are made.

I know the above, and my selection of paint products will not sit comfortably with many of the traditionalists here. However, I justify my choices on the basis of easy and ongoing local availability, price, and ability to use the same products on both the windows and doors (where I was very particular about the colour I wanted on the outside, being now on my third ‘correction’ of choices!). Dulux Weathershield gives the longest lasting protection period of the major brands - 8 years - as well as the factors I’ve already mentioned. The doors come with a 10 year warranty, subject to painting in accordance with specs - all solvent based product on all surfaces and a wash down twice per year.

I did reference my existing windows before asking the questions - although they are of slightly different make up to the new one, plus of course, we’re not broken down into individual components as the new ones arrived! All surfaces in the old ones were painted except for the inside faces of the exterior beads (ie the three strips around the outside of the frame holding the sashes in place). I did also ask the joiner if anything should be left unpainted and he said no. The idea of painting components prior to glazing was that everything was fully protected as possible. He said the fitter will use a silicon spray to ensure the sashes move easily although they will be stiff at first as the seals ease in.

I’m slightly worried now about having painted the unseen edges. The other main paint-paint contact, as you say, is the bottom edge of the sash as it touches the cill. Gloss-gloss is pretty ‘friction sticky’ but in my case it will be gloss-eggshell, if my assumptions are correct, so should be better and there should be time for the paint to harden before being assembled.

As of this morning, the outside faces of the frames (I still need to turn them upside down to final coat the underside top edge and base) look positively liquid in finish and I can only imagine what is going to happen when they’re hooked up and shoved into the cavity! Still, it is even worse for the doors as they are going to be cut down for fitting (so I’ve not put anything on the edges yet - no point!).

I think, by doing, I may have answered my own questions about the division between gloss and eggshell...

Thank you again

 

[fernicarry]

There are inserted V seals where the sashes lie flat on the frame

Yeah, I described how traditional sash and cases would be painted. Being a modern replacement it did occur to me that you might have wiper seals along the edges of the sashes that will prevent them rubbing on the pulley stiles. So, yes, you can get away with painting all of the pulley stiles.

The other main paint-paint contact, as you say, is the bottom edge of the sash as it touches the cill. Gloss-gloss is pretty ‘friction sticky’ but in my case it will be gloss-eggshell

Which one is eggshell? I treat the bottom edge of the sash as external so its done the same as the cill. Depends on how the paint system behaves. I never had problems with Bedec sticking provided it was given a few days to dry. Demidekk on the other hand sticks even after a couple of weeks have passed. I now put low tack masking tape over the bottom edge to try to prevent this.

I'd still think about a different paint system if I were you. 10 years isn't that much in the great scheme of things so the doors would have to be really quite poorly made to require a claim within that period of time. Then you have the bun fight of trying to persuade the supplier that it is their liability rather than you not washing them down "properly". But I'm just a grumpy old skeptic...

Anyway, hope it all goes to plan.

 

[Goldnet]

Which one is eggshell? I treat the bottom edge of the sash as external so its done the same as the cill.

Ah - good point (and came back to my original questions about internal/external interfaces… the cill where the outside sash (top one) would touch down (but almost certainly never would, the fitter will probably fit stays to stop them moving right down because of the springs) is glossed. The edge of that sash should be glossed too as it will be external.

Where the inner (lower) sash meets the cill, I had imagined that half of the cill was internal (there is a 1/4” step up to it) but actually, if the window were open, it would be exposed to wet, so should glossed (ie, the entire cill top surface) as should the bottom edge of the lower and upper sashes. Correct?

Given that I am up to second topcoat with Dulux, and fitters starting on 17th (roofer a couple of days before to remove old windows and repair/replace leadwork), I’m in too deep to change paint system now.

I am also a sceptic and can imagine the face off between door manufacturer (not us, must be the paint) and Dulux (you used solvent based primer instead of our preservative Weathershield water base, so no claim). I hope/imagine, a repaint of these windows in 6-8 years (the time after the rest of exterior due next year - was done shortly after I moved in 5 years ago) will see me out… The current doors are ok apart from a slight warp letting in draughts, which an energy survey picked up. As I had chippie here for the windows anyway, it seemed sensible to use him to fit doors too. I’ll confess to having drastically underestimated the effort in priming and painting. My joiner didn’t offer a priming option unfortunately and in a rural setting, there is only one quality local painter (used another for some rooms and wouldn’t use again - no better than I would have done if I could have been bothered with the prep!), who would never have been able to fit me in with my timescale. I’ve learned a lesson!

 

[fernicarry]

I had imagined that half of the cill was internal (there is a 1/4” step up to it) but actually, if the window were open, it would be exposed to wet, so should glossed

I treat the whole cill up to where the staff bead attaches as external, so all the way under the bottom sash. On my widows its the bottom staff bead that is the first weather seal so water can be forced into the step up bit and it tends to sit there even after more exposed parts have dried off.

The old rotten sashes I took out did have a brush seal along the bottom edge but the groove it was fitted into allowed water to be wicked up into the bottom rail increasing scope for rotting. One looked reasonable from the outside but was practically hollow...

I’ll confess to having drastically underestimated the effort in priming and painting

I hear you on that. I'm still painting my new bottom sashes 5 years after they were fitted. "Just" the inside of the bay windows to do. And its about time to restart the cycle as its nearly 10 years since the kitchen windows were done. Sometimes plastic windows don't sound like such a bad idea after all...

 

[Goldnet]

I treat the whole cill up to where the staff bead attaches as external, so all the way under the bottom sash. On my widows its the bottom staff bead that is the first weather seal so water can be forced into the step up bit and it tends to sit there even after more exposed parts have dried off.

OK - so the entire depth of the cill, wouldn't seem any point in stopping the paint 1cm in from the inside edge where the bead will be fixed. The staff bead will be fully painted before fitting and, if water could sit there, ought to be gloss. As I am not certain which way the moulding will be fitted (groove in straight edge down to the cill or outward facing against the sash), I can gloss that in situ after fitting if need be, which might make a better seal on the junction of the bead with the cill.

The old rotten sashes I took out did have a brush seal along the bottom edge but the groove it was fitted into allowed water to be wicked up into the bottom rail increasing scope for rotting.

The old windows had an inserted encased foam seal along the bottom edge and, as with yours, that's where/why the bottom rail rotted. In another place and another time, a decent chippie could have cut that out and repaired and then replaced the cill but no one seems prepared to take on that kind of work any more.

Sometimes plastic windows don't sound like such a bad idea after all...

The brain says so, the eye and heart doesn't feel the same way. The house opposite is fully uPVC and looks awful. The roofer I wanted to use came with a window fitter mate he works with who told me he only works with uPVC windows so had to start search from scratch. Finding and coordinating roofer, joiner and fitter has been a lengthy and fristrating process. I also had big window firms to quote - when I asked the question "so if I pay this, do you guarantee I'll have no more water leaks", they said of course they couldn't guarantee it, as they don't work on the roof or handle the leadwork!

Another roofer told me I could get conservation grade uPVC windows that were indistinguishable from wood inside the room, or from the street (according to the grade I purchased) but, despite telling me they were putting a local agent in touch, I never heard from them...

The small, local, independent trades I'm using were recommended by the big replacement window firm in the area, via a local window manufacturer who doesn't work in wood but has done the glazing and pointed me to the joiner, who uses this fitter, who said the best roofer in the county is the one who's doing the work. So, all in all, hopefully I will end up with a quality product and fitting.

If I still get leaks, I'll just have to sell!