Retrofit Roof window - attic truss

[Sunshine12]

Hi, I would like a large roof window or balcony style roof window installed.

My question is - is this possible with a truss roof (attic/room in the roof trusses)

The previous owners only installed 1 tiny roof window so it is very dark and unusable as a room. He said they are at 400 centres.

Is this possible? Cheers

 

[noseall]

Is this possible?

Anything is possible depending upon how deep your pockets are and how much disruption to the roof you are prepared to tolerate.

Attic trusses, rather ANY trussed rafter roofs are generally untouchable without going to great lengths to mitigate the removal of the structural elements. Truss rafter roofs connect together as a single working unit with all the elements coming together to stiffen the roof. You couldn't for example trim out a couple of rafters and slot in a metre wide window without consequences or some clever design.

 

[Sunshine12]

Oh dear, that wasn’t the answer I was hoping for.

No deep pockets! Where do I go from here? Thanks for the quick response

 

[TicTac]

Nowhere I'm afraid. If you have a truss roof, then it'll cost a pretty penny to open it up, and that's before you can start to fit the windows (cheapish) or balcony windows (not cheapish whatsoever).

 

[Sunshine12]

Is it possible to fit windows between the rafters? That’s if there are any that slim! I really can’t understand why they had attic room in the roof trusses but no windows

 

[Sunshine12]

Presume adding a dormer poses the same problem of cutting through?

 

[TicTac]

Post a picture of inside the loft. It's just possible that we're talking at cross purposes.

 

[Sunshine12]

Thanks Tic, it’s all plastered & painted so not sure if that helps

 

[TicTac]

Sooooooooooo, there's already a room in the attic, and it's got a small window, and you want a bigger one. Sorry, that wasn't evident from the first post.

If it's been plastered, then you need to knock off the plaster to get at the joists, and work from there. So back to the last request; post some pictures of the attic, and the window you've got in there.

Work with us Sunshine, pretty please.

 

[noseall]

Presume adding a dormer poses the same problem of cutting through?

Yes, same principle.
Generally, a large opening in a truss rafter roof is planned for and designed from the outset. Compound/girder/multi-ply trusses are used either side of an opening and then trimmers and purlins span onto these support trusses and carry any loose-fill rafters etc.

It is difficult to retrospectively introduce these support trusses into an existing roof. A clever designer may be able to use existing internal walls and steel in order to achieve what you want.

 

[noseall]

If it's been plastered, then you need to knock off the plaster to get at the joists

Why will the OP need to expose the joist (bottom) chords? What will that gain?

 

[TicTac]

So how do you suggest he fits a bigger window without knocking a few holes in the plasterboard. I can't wait for the reply on this one.

No seriously; I think the OPs set us off in the wrong direction, so we're approaching this from the wrong angle.

 

[bobsuerita]

attic trusses are added to a lot of houses as a bonus when coming to sell as there is peanuts between the cost but they are left unfinnished

it can be done if they are spaced at 400cc then you could put 780 wide veluxes in no problem an ideal place will be oppisite staircase as this area will be cut
as you can see in this photo for these veluxes the t trusses cut instead of infill ignore the fact they have been doubled either side as these trusses are a 17m un supprted span so a bit more involved
you will proberly have to take the plasterboard of the whole sceiling side you want them just get somone that knows what there doing not just some general builder

 

[Sunshine12]

Thanks for the responses. Tic-tac- apologies I didn’t make it clear. It is a plastered ‘finished’ room with electrics, heating etc but only 1 tiny velux that isn’t possible to actually see out of.

When we bought the house the seller said he had a new roof with attic trusses & he used it as a cinema room so I guess that’s why it’s so dark. But now we desperately need the space as a 3rd bedroom, preferably with some natural light! There is a standard staircase & fire door.

I don’t mind knocking off some plaster & exposing trusses but obviously I have no idea what exactly I’m looking for. All I know is the centres are 400 & the current Velux is as you get to the top of the stairs.

Is it possible to have anything at all installed with 400 centres?

Bob I did find a balcony style window at 780 which looks great but don’t want to waste peoples time getting quotes if it’s not possible

Cheers again

 

[noseall]

So how do you suggest he fits a bigger window without knocking a few holes in the plasterboard. I can't wait for the reply on this one.

I think you meant 'rafters' and not 'joists'. Cant wait for you to refer back to your Building Terminology handbook.