Changing window size?

mikeoc85

Hi all,

A strange question I’m hoping someone might be able to help me out.

We’re currently building an extension to our kitchen. It’s a vaulted roof and walls on either side are 3200 high, room is 500 meters wide and roof pitch is 35 degrees.

We’ve planned a fixed window of 3200 x 2200 towards the back. Our problem now is we just found out we might not be able to get a window that big in Ireland without support beams - which we don’t want.

Builder is onsite right now and what I’m wondering is if we have the openings that big for the window and can’t source a window that big, how difficult would it be to bring the opening down 200mm after the fact for a smaller window?

Seperate question, the roof looks a bit high now that the guide rafter is in, we were happy enough with 3000 but engineer recommended 3200 for aesthetics and we naturally took his advice. What we’re wondering is, how much lower from the underside of the guide rafter will the finished plasterboard for the vaulted ceiling be?

10-10-20

Bring the top of the window down 200mm… would be tricky as there would already be a lintel in place and there isn't an easy solution to drop it, unless the builder has other ideas. Raising the bottom of the window 200mm would be more achievable from a builder's stand-point, but may not be possible due to access issues, etc. Best talk to the builder, arch, QS and eng on that and come to a compromise.

engineer recommended 3200 for aesthetics

Isn't that the architect's job? But the depth of the plasterboard off the rafter might only be a couple of cms, but depends on the roof make-up including the insulation detail. I would think that it's best to review the drawings on that.

mikeoc85

Thank you very much for the response

so when you factor in insulation, wiring, space for ventilation etc this is fixed to the bottom of the rafter and only be a couple of cms in total?

there’s no lintels etc in place yet, the side with the window hasn’t had its walls constructed…only the two side walls

Mellor

https://www.boards.ie/discussion/comment/123981923#Comment_123981923

Isn't that the architect's job? 

My thoughts exactly. It’s “domestic engineering” is a broad enough brush as it is. Let’s not defer to them for everything.

10-10-20

https://www.boards.ie/discussion/comment/123982405#Comment_123982405

Plasterboard alone (with insulation between the rafters) could be anything from 8mm to 12mm, plaster on top of that of 2mm to 4mm, so under 20mm total.

But insulation, plaster board and plaster could be anything from 55mm to 150mm depending on the insulation plan.

mikeoc85

https://www.boards.ie/discussion/comment/123982478#Comment_123982478

thank you, so we could say in theory have the finished roof sitting between 55mm and 150mm below where the guide raft currently sits?

10-10-20

https://www.boards.ie/discussion/comment/123982864#Comment_123982864

It could. All depends on what the design entails.