Bay window curved batten - what material?

[rarara]

Victorian flat and the north facing living room has a really cold bay window so the time has come for curtains. Above the windows is lath and plaster with a bit of a gap behind. I think eventually (maybe 12 inches) I can reach some sandstone to fix a batten to, but I have a few concerns....

1) What material should I use?

MDF looks quite bendy, so would fit the curved profile i'd imagine - not sure it's the best material to screw into though for the curtain track (they will be heavy as 3m drop). Would proper wood like pine, or even a strip of ply be better? And thickness?

2) The bay is over 4 metres, so is it advisable to use several individual sections rather than one whole length?

Obviously one section would have more integrity, but i'm not sure how easy that would be to offer-up, add adhesive to, hold in place etc while I tried to find something solid to fix behind the lath/plaster. Any advise or things to avoid?

 

[Harry Bloomfield]

Above the windows is lath and plaster with a bit of a gap behind. I think eventually (maybe 12 inches) I can reach some sandstone to fix a batten to, but I have a few concerns....

I would rip that lath and plaster down, adding insulation, then plasterboard over the top, before worry about fitting battens to fix curtains to.

 

[Deleted member 174758]

I agree with Harry, but assuming you do that, best in mind that plasterboard can bent to a radius by soaking in water then leaving overnight with the ends raised above the centre on blocks or timbers. You will need to install softwood packers or formers between the masonry and where the back face of the PB should go. The more the better , but certainly at least every 400mm and better every 200 to 300mm. You may be better making up a couple of curved ladder frames frpm softwood and OSB, chipboard or plywoodand affixing them to the joists above then the PB to them

1) What material should I use?

You could kerf bend softwood, but it will take a lot of time to achieve this and consistency of kerfs is paramount. Personally I'd go for a curved piece made up by glueing and screwing or pinning three to five thicknesses of 6 or 8mm MDF together, in situ. This will need to be done carefully and your joints will need to overlap. Get a timber yard to rip the strips for you so they are consistent. 40 to 50mm wide should do. Despite looking quite bendy, 18mm MDF won't bend that well - 6 or 8mm will. See below for further fixing details

2) The bay is over 4 metres, so is it advisable to use several individual sections rather than one whole length?

You simply won't get a single piece that long to bend the way you think. Also standard sheet material, for example is 2440mm long (8ft)

one section would have more integrity, but i'm not sure how easy that would be to offer-up, add adhesive to, hold in place etc while I tried to find something solid to fix behind the lath/plaster.

When you replace your lath and plaster you need to install softwood packers between the masonry and the back of the PB. Mark where these are and you can use longer screws to fix through the curtain rail batten and PB and into the softwood packers for a better fixing

Edit: Please bear in mind that this suggestion is made in the knowledge that the OP has very limited woodworking experience so techniques like using bendy plywood (expensive), steam bending - water bending would be very likely to fail (expensive, dangerous, experience required, high failure rate), solid timber lamination (experience required) or bandsawing (equipment required) are off the table

 

[rarara]

Argh - this all seems overcomplicated for hanging a pair of curtains . The idea of replacing the L+P is not appealing, and would very much only be a last resort.

Think I will need to create some holes to see exactly how far from the underlying stone I am (there are no obvious or useable joists unfortunately) and how easy it is to get fixings into it. And get some MDF strips cut and build up a few layers once the first ones are secure.

 

[JohnD]

The laths will be fixed to a timber frame running at right angles to the laths. Most likely uprights. Locate them and screw into the timber. They are probably around two feet apart.

Start with a powerful neodymium magnet to find the original nails.

You may even be able to see them by shadow staining of dust on the wall.

 

[opps]

You don't mention what kind of curtain rail you plan to use.

My home has a hockey stick window bay. Originally it would have have had curved Crittals windows but they have been replaced with straight uPVC windows. We decided to opt for plastic Swish rails but the fittings didn't project far enough in to the room to clear the architraves. I cut up sections of 25mm copper pipe to push the fittings forward (and then used long screws to reach the wall plugs.

My walls were solid but as @JohnD said you should be able to find the solid timber.

Another alternative, again if using a plastic rail, might be to fix to the ceiling but that could be tricky if you have a large cornice.