Bay window construction

[nelliedee]

Hi

We have just had a smallish double glazed bay window fitted and were rather hoping to put the roof on it ourselves. We hoped someone could point us in the right direction of a metal company that make small lead roofs? we are london/surrey borders.
Also can anyone do a sketch for us of the timber construction needed to support this said roof which will measure approx 5ft wide by4ft high by 2ft out (depth) if that makes sense?

We have only 4 inches between top of window to underside of guttering.

Thank you for any help
Nelliedee

 

[Xenon]

Some pictures will help. Are you sure you want lead? probably the most expensive option after Copper.

 

[nelliedee]

I assumed Copper was more expensive but will now look into copper.
I cannot photograph the window as camera is broke. I cant draw very well and wouldnt know how to add a drawing to this thread

Nelliedee

 

[Xenon]

Copper is mor expensive, re read my post. Here a a couple of very simplified sketches. Felt would be the cheapest/most cost effective option.

 

[nelliedee]

Hi
Sorry just reread your post

Thank you for the drawings they will help hubby and me to plan this roof.

I am having problems visulising how the joists attach to the top part of the window? or do the joists just rest on top of window.
Have tried to show an image hopefully you can see it below in my images called nelliedee

Nelliedee[nelliedee] [GALLERY=media, 4034][/GALLERY]

 

[Xenon]

Need to see detail of window head really.

 

[nelliedee]

Managed 2 piccies
Let me know if you need more detail View media item 4036 View media item 4035

 

[noseall]

the exposed underside and topside of the window structure requires full insulation.

it does mean ugly fascia at the bottom window detail too.

 

[Xenon]

I see a couple of problems. You are going to have to fit the joists on top of the window frame. This means you are reducing your upstand height so may need it behind the facia. You can rockwall between the joists before you put the ceiling up.
Its not as straightforward as it may seem imo, a good roofer should overcome it easily enough, without adding to much cost to the overall job.

 

[nelliedee]

Hi Noseall

We were wondering about the insulation below the window sill as otherwise its gonna be so cold. Had a look at other properties and none have facia or insulation underneath. Is this a regulation or reccomendation?
Nelliedee

 

[nelliedee]

Hi xenon

So we need upstands on top of window and attach joists to the upstands?
Do we just sit upstands directly ontop of window? do we attach it to window?
Nelliedee

 

[noseall]

. Is this a regulation or reccomendation?
Nelliedee

as far as b.c. are concerned then take it as a recommendation, though i would be inclined to check.

 

[nelliedee]

Thanks Noseall, will do
Nelliedee

 

[noseall]

B.C. once informed that a bay window falls under the same regulatory criteria as a regular extension.

therefore it must comply to the same part L standards as any other extension.

this explanation was applied to a ground floor bay only, which obviously involved walled elevations and was not a predominantly glazed structure.

 

[Xenon]

Easiest way would be to deck it with inch ply, at that width, joists won't be required, but you will then have a problem insulating it, and the drip detail will be shallower than preffered. Without cutting a section from the facia/soffit, and stop ending the gutter and diverting it, you will have trouble getting a decent waterproofing upstand height. You need 150mm but you're already only 100mm away from the existing gutter.

The correct way would be a 3x2 on the window head with a facia around the edge, the deck sailing over the facia 25mm for drip detail. But you are restricted by height. The bottom can be clad/insulated easily if you have an angled detail.