Pointing around windows and removing paint from sandstone

[fernicarry]

A couple of weeks ago, after the hot weather, I thought I'd have a poke at the windows in the hope that there might be something salvageable with some hardener and filler. It was worse than I expected ... much worse.

I've now had a couple of guys round to quote and we're looking at 8 new sills, 8 sets of pulley stile repairs and between 4 and 7 new sashes depending on how keen they are to repair as opposed to replace. Only one sash still has wavy glass and both are willing to make an attempt at saving that. I think all the downstairs ones must have been replaced in the not too distant past judging by the colour of the wood, most likely by a large national company beginning with V...

The bit I'm struggling with (other than the cost...) is the pointing between the window frame and the stone. Its dressed sandstone around the openings with about a 1.5" gap between the window and the stone. Over the years its been patched, filled and over-painted to the point that the paint line now overlaps the stone and its all cracking and delaminating and generally very unsightly. Both would rake it all out. Guy #1 wants to fill the gap with expanding foam with a trowel applied mortar over that. There is a gallery image on his web site that looks very neat. Guy #2 wants to use a modern gun applied mastic and then recommends overpainting. #1 would be fine except for the expanding foam obviously.

So I suppose I'm looking for ideas on how best to back fill the gap before putting a finish on top? Another thread here recently suggested expanded metal of the sort used by plasterers. I can see that working but not a tradesman wrestling with it. Whats actually in there at the moment, at least on some of the windows, is a sort of foam sausage (backing rod?). Whilst not ideal, this is at least easy to remove in the future since its just held in by friction and shouldn't be too time consuming for a tradesman to apply. Any thoughts? The same foam was under the sill and in its defense it was absolutely bone dry.

Secondly, I do want to get the paint line back to the window frame rather than over-painting the mastic. Whats a good approach to removing the existing paint on the sandstone? Will chemical strippers like nitromors work without causing damage? The paint does seem to come off reasonably easily with a bit of chipping but thats probably because a thin layer of sand comes off with it.

Thanks all.

 

[Feltwell]

I've had a not dissimilar problem here, I packed the gap with pieces of roof tile and pointed it all up with lime mortar. I've still got to mastic back to the window frame - I'll be using a modern overpaintable cartridge-type sealant for this, I tried the traditional burnt sand mastic but it all started to fall off within about 3-4 years.

I can see expanded metal lath working. Not convinced about foam sausages! - I suppose it could be closed cell, so doesn't absorb water, but still a bit radical for me!

Paint on sandstone - a test pack from Strippers of Sudbury would be my first thought, and try it somewhere unobtrusive.

Another option is some extra wooden moulding trim around the window to hide a gap, I've done that successfully on my bay window, looks like it was always meant to be there.

 

[fernicarry]

Thanks Feltwell. I think the sausage is closed cell. Looks and feels identical to the grey foam pipe insulation. And actually the stuff on the left of the window had been reduced to little granules of foam that I vacuumed out, which is exactly what the mices do to the pipe insulation under the floor. So its kind of biodegradable...

I don't particularly want to overpaint whatever fills the gap. I rather like the look of a contrasting mastic around the window. Guy #2 did make the point that he doesn't use traditional mastics because they don't last. He wants to use Fosroc Nitroseal, what do you use?

I suspect where I'm going to end up is getting guy #1 in to do just the wood repairs, which are now rather urgent due to the big bay window having almost no bottom rail left! Once that's done I'll get the rest of each window overhauled and painted and ponder what to do with the pointing.

 

[plasticpigeon]

I have a similar problem. I need to run a fillet of something strong and flexible along the front edge of the wooden sill where it meets the stone sill beneath. I'm sure there must be a flexible sticky overpaintable sealant that will do this but what? Roof and gutter sealant?

 

[Feltwell]

I have a similar problem. I need to run a fillet of something strong and flexible along the front edge of the wooden sill where it meets the stone sill beneath. I'm sure there must be a flexible sticky overpaintable sealant that will do this but what? Roof and gutter sealant?

Lord No, don't use that - it's black, tarry stuff. Great for sealing cast iron gutter joints but I wouldn't use it anywhere else!

I used this when bedding new wooden cills onto stone, as it's both clear and overpaintable I figured it would be unobtrusive - and it is. Seems to work fine.

https://www.screwfix.com/p/geocel-the-works-sealant-adhesive-clear-290ml/92565

 

[Feltwell]

Thanks Feltwell. I think the sausage is closed cell. Looks and feels identical to the grey foam pipe insulation. And actually the stuff on the left of the window had been reduced to little granules of foam that I vacuumed out, which is exactly what the mices do to the pipe insulation under the floor. So its kind of biodegradable...

I don't particularly want to overpaint whatever fills the gap. I rather like the look of a contrasting mastic around the window. Guy #2 did make the point that he doesn't use traditional mastics because they don't last. He wants to use Fosroc Nitroseal, what do you use?

I suspect where I'm going to end up is getting guy #1 in to do just the wood repairs, which are now rather urgent due to the big bay window having almost no bottom rail left! Once that's done I'll get the rest of each window overhauled and painted and ponder what to do with the pointing.

Contrasting mastic is not very period, but more importantly if it's not neat or starts to go a bit grotty..... Not heard of Fosroc Nitroseal, looks like it's polysulphide sealant, they do work well. Not sure if you can overpaint them or not.

At the distinct risk of sounding narcissistic (as I've referred back to it a few times now to different folks! ) this old thread may be of interest. Not saying it's the right way to do it, just the way I chose. Has worked well and I'd do much the same again (but hopefully won't have to!)

http://periodproperty.co.uk/forum/viewtopic.php?f=1&t=16118&p=219945&hilit=bay+window#p219935

 

[fernicarry]

I am a big fan of your work, feltwell, and it has definitely inspired me to take on a few things on my own, but this is just beyond what I could hope to do in any sort of reasonable timeframe so will have to be done by the 'pros'.

 

[fernicarry]

I dismantled one of the bay windows over the weekend to get it cleaned up for paint. Unfortunately Mr Squirty Foam has already been at it. At least 3 rounds of repairs judging by the dates on the newspapers -- 1966, 1981 and 1997. Every 15 years roughly so we're overdue. Some of the foam just dropped out but quite a large section had a really good grip on both the stone and the frame and a huge blob had expanded into the weight box :evil: . I think I'm also going to need some sandstone repairs before its ready to repoint as large chunks of earlier cement repairs came out with the pointing.

Now that I've got it all apart I think I'd be willing to have a go at the stile repairs. They've all been repaired before and its obvious how its done. These were no where near as thorough as feltwell's with the repair section just nailed through the stile. With the expanding foam out the whole thing is quite wobbly, no doubt a 'pro' would insist this makes the expanding foam necessary. Less sure about the sill. I suppose that gets a lot easier once the stiles are cut back as you can put the new sill in at an angle. But, it would still take me an age so I'll let the chap go ahead and I'll carry on with the de-Ventrolla-ing and painting. Big tin of MSP on order.

Also, I think I know why the walls on either side of the bay recess get a damp tide mark in winter. The inside of the wall was completely filled with debris up to at least 12" above floor level. Mostly sand and bits of plaster. So any water that penetrates even part way into the stone can track across into the back of the plaster. Henry filled two bags sucking it out and still not reached the bottom. Can't get to it from underneath unfortunately because there is a sleeper wall across the bay. I'm trying to route some alarm wiring up to those windows so was hoping I could rod straight down from the weight boxes but this debris is preventing that.

 

[Feltwell]

If it's in the weight box, I think just smacking the weight into it a few times will break it up if it's in the way. I know squirty foam *can* have it's uses but I've never comes across it anywhere other than being used as a bodge.

My porch roof, that came off the other day, had foam in place of a roof joist end :roll: Mind you, as the rest of the joist was basically compost, so it was doing a better job than that!

It also revealed a copy of the Daily Express from 1980. Apparently our relationship with Europe was a big problem and no one trusted our politicians to sort it out. Who says history doesn't repeat itself? :lol:

 

[Flyfisher]

My porch roof, that came off the other day, had foam in place of a roof joist end :roll: Mind you, as the rest of the joist was basically compost, so it was doing a better job than that!

It could be that the foam had hastened the demise of the joist.

That was certainly the case in a few places on our roof where the leaking roof had been 'fixed' by squirting foam into the area where the water was getting in from inside the room affected! It worked to an extent, ie it stopped the water entering the room but of course it did nothing stop the water entering the roof and it simply trapped that water around the joists, preventing them from ever drying out properly and helping them on their way to compost. :evil:

Goodness knows what that spray-on loft insulation foamy stuff must do to roof structures. :shock:

 

[Feltwell]

Goodness knows what that spray-on loft insulation foamy stuff must do to roof structures. :shock:

Yes - "Don't bother fixing your roof with the slates that are slipping, just squirt this stuff and it'll glue them in place and insulate as well!". Ohh how roofers must love that stuff when the inevitable comes! That must have hastened the demise of many an old roof.

Main cause of my joist's demise was being bedded next to, and in direct contact with, damp stone along one side of it's entire length with cement mortar. Lord knows why - totally unnecessary. Stone is dry now, too destructive to remove the cement but the new joist is both treated timber and spaced about half an inch away, so air can get round it.

I've never understood why folks point up all around joist ends with mortar, where they go into holes in brickwork - it's not really doing anything except possibly trapping damp in, surely better to let the air get round them a bit? They're always prone to rot. I made sure these were well treated on the cut ends and then firmly wedged in place with bits of old tile & slate.

Another topic meanders merrily away from the original post, sorry Fernicarry!

 

[fernicarry]

No worries on the off-topic. Today was a garden day so nothing to report window-wise. Should have been a paint day but the Old White MSP is out of stock at the place I ordered it from.

The new pulleys did arrive so I'll start getting those up tomorrow with any luck. The Scottish-size parting bead is back ordered. Which reminds me that after fitting the proper thickness parting bead to one window at the weekend I realised that the meeting rails no longer meet. One of the Window Men had mentioned that the Company Whose Name begins with V plane down the meeting rails when they do their draft proofing and that must be so that they can fit skinny 8mm beadings (using gallons of silicone to fill the 14mm slot...). The top sash should be ok because the parting bead is still flush to the outside edge of the slot, its the inside facing edge thats filled with silicone which means that the lower sash must be modified so that it sits closer. Fingers crossed that the replacement lower sashes are the correct profile.

I did manage to rod the alarm cable into place yesterday. Turns out the floorboards in the bay are supported at each end by on the lower part of the bay wall so the interior wall void isn't open at the bottom like that on all the other external walls. No way to rod straight down and explains why there was so much debris in there. I managed to get through from under the floor at the corner where the bay meets the room proper. First time actually which was a bit of a shock. When the old sills come out I'll loop the cable across under all 3 windows and then mortice an alarm contact into a pulley stile of each. Will make for a nice discreet install. I hates surface run wiring of any sort...

 

[fernicarry]

Got a bit of a shock last Thu when the Window Men turned up at 8am. Only 7 days earlier than I was expecting!

So I now have new sills, repaired stiles and new bottom sashes in 7 out of 8 front windows. One of the upstairs sashes still had wonky glass and I'd already asked him to try removing that and putting it into the new sash. He agreed rather too easily and I was a bit suspicious when the replacement turned up already glazed. Then he announced that the new one was a different size so glass replacement would be a non-starter :roll: . I've saved the old sash in case the glass can be used somewhere else. All but one of the downstairs sashes were relatively recent which explains their horrible state and given that the new sashes really weren't that expensive I can't feel too bad about scrapping them. I promise to look after these ones better...

Its been full-on stripping, sanding and painting since then. Someone on here mentioned the Bahco 625(?) stripper. Well, I can vouch, it is incredible. You can get down to bare wood in no time at all. Even the external paint that is several millimeters thick eventually succumbs to this thing.

Still no decision on how to do the pointing. Window Man insisted that squirty foam was really the only feasible solution and predictably trotted out the line about how it helps support the cases. He did mention he'd been on a conservation stonework course...

I've been thinking about replacing the flat lead roof above the bay but when we took out the windows above it found that the lead is actually lapped right under the sills with an upturn at the end to form a sort of shallow basin. Is this a normal arrangement? Means that if I redo the roof will need to take the windows apart again. Also found a metal downpipe running down inside the bay wall which I presume at some point was to drain the flat part but no evidence of an opening at the top anymore. I'd seen the bottom of this poking out under the floor and wondered what it was. No idea if its connected to anything or is sound enough to consider using.

 

[Feltwell]

DJH (Doug) is the resident leadwork expert, if you put up some pictures I'm sure he'll advise.

My bay would originally have had a 1" diameter lead pipe to drain from a hidden gutter, which must have blocked up constantly. Gutter now discharges via a lead spout into a hopper, much more practical arrangement which never blocks.