Leaking wooden window beads causing rot

[thesled]

Hi

I've been working at friends house to try and fix up some modern(ish) doors/windows that are double glazed with the glass held in by wooden beads. What seems to have happened is that the beads are just no good (unlike putty windows) at keeping the water out. As a consequence, water seems to have soaked down into the wood below, worst on the door which has totally rotted out and is basically scrap although I will probably bodge it up for now. Have to say unlike traditional putty this system seems useless !
My plan for now is to devise some sort of system to set the bottom bead in some type of mastic to completely seal it, leaving some little drain holes above so water running down can run off doesn't get trapped.
Any thoughts from those who have dealt with similar problems I'm very interested to hear.
I picked up on the offchance some window bead in Wickes ('Cheshire Mouldings') which is almost correct for the window, it's just too deep. I could (but don't fancy) cutting it down lengthways but if anyone knows a good stockist of these profiles I'd be interested to hear.

Thankyou !

 

[ronniecabers]

There are several potential causes for this.
someone skimped on the sealant when the windows were glazed
Beads not 'capped 'once glazed
Rebates werent treated before glazing
maintenance ( eg painting and staining )on the windows/doors wasn't kept up

Putty dries out and cracks , letting water in , I'll tell you now NO manufacturer of sealed units will warranty any unit put in with putty in today's market, in fact less and less warranty into wood at all due to the above reasons I mention

Looking at the pics , at least 2 of my reasons above are very valid!

 

[thesled]

Thanks Ronnie

OK So I'm learning some stuff here

The rebates should have been, what, painted before the glass was put in?

With the sealant, well there isn't any! But then I noticed - my front door, which is a 'composite' type. The trim/beading seems to be actually bedded in sealant (pic attached) - is that more what should have been done? But then I've seen some people say this is counter-productive because it could actually trap the water - I guess it's OK if done all the way round. And all sides are sealed.

Fear not - I've no intention of using any putty on this - it would look pretty odd if nothing else - although any consideration of warranty claims are long gone !

Regarding 'capping' the beads - don't know what this actually means - any helpful hints gratefully received.

Sounds like the short answer is that the system does actually work if it's done properly in the first place.

PS - 'maintenance ( eg painting and staining )on the windows/doors wasn't kept up' - definitely not - it's all been neglected for years, though I'm not sure if just painting the beading would have helped stop the water getting in behind it.

 

[ronniecabers]

Unless the bottom bead has packers and allow drainage then the recognised way of fitting the glass would.have been to fill the void around the sealed unit with a clear Low Modulus Neural cure silicone, thus not allowing any water to get to the seal of the unit, this would protect the sealed unit ( note you do need to use a glazing packer to keep the glass from the wood.

Prior to fitting the rebate and non visible surfaces of the beads should have been either treated ,primed or sealed , paint, varnish, sealer .. whatever your wish to use
There is some debate as to the effectiveness of using a glazing tape tonfix the sealed unit in the rebate and on the beads prior to fitting ( the face of the rebate , not the gap created) . I have seen silicone and tape used , both lasting a long time also both failing quickly.
Do not have sealed units that are taped on their edges , the tape can hold any more moisture.
Once the beads are nailed/pinned in , then I usually run thin bead of silicone around where the external beads touch the glass ... this is 'capping '
The lack of maintenance would have meant the beads/frames were probably letting water in anyway.

Ive not written that in the right order really but think you get the gist of it .

Basically make sure frame /beads are prepared correctly
Fit glass and fill void
Fit beads
Cap beads
Keep on top of restaining/painting , any pins working loose and the silicone capping ( glass and wood contract and expand at different rates so gaps can appear and just need resealing )

 

[accelerator]

I'm not a window expert, but for the bits of wood (beads) used, they should have been fully treated with preservative before being fitted, and then some method used to prevent water getting into the gap between glass and wood. The fact this wasn't done has led them to rot out. Painting once they are in situ is not enough.

 

[ronniecabers]

I'm not a window expert, but for the bits of wood (beads) used, they should have been fully treated with preservative before being fitted, and then some method used to prevent water getting into the gap between glass and wood. The fact this wasn't done has led them to rot out. Painting once they are in situ is not enough.

Absolutely!

 

[thesled]

Thanks Ronnie

Much obliged to you for taking the time and trouble to write that out. Yes - I am indeed getting the general idea - lack of proper preparation, sealing and maintenance doesn't help this system to work well! I will repair on the general principles laid out - though as I've said the doors are shot anyway so it only needs to be an 'interim' measure - but which if I get it to work will probably be there for years . . . . .

Accelerator - that does indeed seem to be the issue- unfortunately we are probably too late to save the doors but will be a useful practice exercise!

I should add the problem is made worse by being in a rather damp area. It is buried in a 'cave' created by a big kitchen extension and doesn't get much sunlight to dry it. Also the house is near a river. . . . .

 

[accelerator]

Sikaguard clear wood preserver would be a good treatment for the new stuff.

 

[mrrusty]

Get new beads - you can get both Accoya and synthetic wood beads e.g. https://www.reddiseals.com/product-category/sash-window/beading/reddibead-wood-plastic-composite/ and https://quantumprofilesystems.com/qwood/qwood-window-profiles/

Buy a roll of this and when you pin the beads on to a bed of sealant push the lip tight to the glass - it creates an excellent seal without the squidginess of using sealant between bead and glass https://www.reddiseals.com/product/flexible-epdm-tape-with-lip/

As an alternative to epdm tape you could use flexistrip https://www.reddiseals.com/product/...9b8T0xckzvvz2cqI40vSq148WdSectG3QeRWKrTE39LyS which is sticky both sides and forms a flexible seal between bead and glass

 

[thesled]

Great suggestions mrrusty I will check those out thankyou

There's a whole world of stuff out there it seems - once you know where to look. Look forward to seeing how it all works.

Had a quick look at reddiseals and seem they do a lot of sash window stuff too, which is great as I'm up to my neck in that as well . . . . .

 

[mrrusty]

they do a lot of sash window stuff too

7 of the windows in my house are sashes I made from scratch, so a few lessons learned along the way - start a new thread on anything you need to know...There are also some real experts over at UKWorkshop woodworking forum who make and repair sash windows

 

[Notch7]

just a pointer here: timber windows with modern double glazing should not have the double glazing encapsulated

typically the window rebate is 18mm the window spacer bar is 12mm and if the spacer bar is flush with the edge of the timber (the sight line) then in theory there should be a 6mm air gap all around the DG unit.

if wet glazing with silicone, the DG unit is put in with glazing packers all round, then a bead of silicon is put in around the gap to seal it -but not filling the gap up.

the bottom bead should have a line of silicone on back of bead so water running down the glass cant get in.



it is vital at the bottom that there is a min gap of around 5mm and that the bottom rail has holes drilled so any water getting in can get out, or in case of doors a project bead is fitted and there are slots for water to get out

yes the rebate and glazing beads should be fully painted and the glazing bead mitres should be siliconed

if it fits you could get Q wood beading

Timber Window Glazing Beads | Qwood

Qwood offers a complete range of high quality glazing beads. Qwood works perfectly with timber to make a better timber window.

quantumprofilesystems.com

this sort of beading is great because it has a tiny rebate so you can silicone with some MS polymer sealant to seal between glass and bead all way round (dont use silicone here as its not paintable)

 

[ronniecabers]

Completely agree Notch, modern wooden glazing is glazed dry.. from the pictures this does not look like modern wooden frames though

 

[Notch7]

Completely agree Notch, modern wooden glazing is glazed dry.. from the pictures this does not look like modern wooden frames though

yeah they look like 4-6-4 units -pretty old

 

[thesled]

Thanks for your further thoughts on this folks. Quite a bit of detail to get my head around, but it seems the general principle is straightforward - stop the weather getting in but allow drainage if it does. Makes sense to me.

We think the windows/doors are most likely late 1990's, possibly early 2000's at latest. With the window (white) its mainly just the bead that has rotted. As you can see, the underlying frame wood is *mostly* OK although it is a bit rough right at the bottom edge but I'll most likely just patch that in with a bit of white hybrid. Don't know if this was caused by water getting under the bottom bead or just running down the outside and under the edge.

With the doors, I need to have a bit of a closer look at some less damaged bits, but it seems all they've done once the DG unit is in is just put wood beading round to finish it. I don't see much evidence of silicone, drainage provision or anything described above. You'll see there's a gap between the DG unit and the vertical bead allowing water in. However it's all a bit of a moot point - the door frames are basically rotten at the bottom and will ultimately have to be replaced but I'll probably end up patching them up in the meantime, so will attempt some basic measures on the principles given to protect any repairs I end up making.