Bending Battens to Curved Bay

[wingit]

I'm renovating my bay window, circular segment kind of design. I need to bend some wood to form the tile battens.

I already tried kerf bending some roofing battens, but with the knots and general quality of the battens, it wasn't working, they crack and split too easily, even when soaked.

They need to be four metres long, so I was thinking that even if I steam them, by the time I've formed part of the curve they'll have cooled down enough to make curving the rest of the length too difficult.

I'm now thinking I need to either get some good quality wood and kerf it, then paint on preservative, or laminate it. Can anyone recommend a good choice of wood for this purpose? I did play with the idea of laminating together 6mm marine ply in four layers, but I don't think it would be strong enough to hold the tiles in place securely.

What would a roofer normally do? Just cut sections of roofing batten to form a rough curve?

Thanks

 

[palaceray]

You may find the easiest way is to buy 12mm lath as this will bend Around the curve easily. You can double it up to give a good thickness. If it is still too bouncy to nail the tiles, then you can screw them.

 

[wingit]

You may find the easiest way is to buy 12mm lath as this will bend Around the curve easily. You can double it up to give a good thickness. If it is still too bouncy to nail the tiles, then you can screw them.

Thanks, it doesn't look very easy to find four metre lengths. So, at the joins, because they will be under tension from the bend, I imagine there is more likelihood of a weaker fixing. Is there any technique to limit that?

 

[bobasd]

Good suggestion above but surely there's no need for anything but tile battens?
I've never had difficulties bending around bays etc. and always used clout nails.
Start on the middle stud, and work the battens sideways.
Pilot hole and screw at the joins if you must, and angle the cut or pack out the stud with an off-cut of one by for bearing.

 

[wingit]

I've never had difficulties bending around bays etc. and always used clout nails.

Is that using 38x25mm battens?

Maybe I bought poor quality battens, but even when I soaked them, they broke at the knots. The curve is quite a lot.

The original battens from 90 years ago that I removed, were hardwood 1/2 by 2 inch

 

[wingit]

or pack out the stud with an off-cut of one by for bearing.

could you explain that one a bit more please, I can't get my head around it

 

[bobasd]

yes, 38x25battens.
in that case then do short lengths across a couple of bays or so.
Or, Kerf the back of the battens.

 

[bobasd]

simply fix an of-cut to the side of the stud making say a 40mm stud into a 50mm stud.
you could use a tile batten for this.

 

[wingit]

simply fix an of-cut to the side of the stud making say a 40mm stud into a 50mm stud.
you could use a tile batten for this.

ah yes, thanks

 

[catlad]

Can you not bend them over several days with weights or clamps before you intend to use them.

 

[noseall]

Use two layers of 15mm thick MDF 50mm architrave. You can tie that stuff into knots.

 

[datarebal]

decent quality batten, either cut in shorter sections or ply strips

 

[wingit]

Use two layers of 15mm thick MDF 50mm architrave. You can tie that stuff into knots.

problem is, it's a 'cold roof' bay, and moisture would be present

 

[noseall]

problem is, it's a 'cold roof' bay, and moisture would be present

Strips of 9mm ply could work just as well.

 

[wingit]

Can you not bend them over several days with weights or clamps before you intend to use them.

I tried bending them, using hot water, over a few hours, but one snapped in two and another started splitting. So it would be a lengthy process. They would dry out overnight as well, and I noticed they creaked and sounded like they would crack as they dried out. I think it would just take too long to them all that way really.