extending pitched roof

[turnpike]

i have a roughly 3 x 5m pitched roof kitchen extension. alongside it is a flat roof garage about the same size. i've already been given advice here about a few things re this rebuild, thanks (noseall and co).

i'd like to have a single (even) pitch roof over both. is it likely assuming no complications that the existing pitch roof can simply be added to, making it higher and wider? or does a pitch roof have to have joists which span the width in one piece? i.e. be built entirely from new joists and rafters?

the wall between the two buildings is not being removed so the wall plate there stays.

i'm not doing it myself obviously but just wondering about various suggestions i've been given.

 

[advancemaintenance1]

hi mate could you upload a picture or two i can visualise what your saying but would like to give you the correct advice as there is a couple of things that are possible cheers

 

[turnpike]

hi. here are a few sketches. i'm just wondering if a new pitched roof is a case of taking all the old roof rafters and joists off and starting again, or if the new one can be built either without moving any of the existing one or maybe just taking the rafters away and somehow just adding more joists for the other building.

if the pitch needs lowering (which it might) then obviously the rafters have to be replaced. but do the joists have to be replaced or can they be left in place and added to?

the kitchen extension (left of the 2 small buildings) is double skin brick no cavity. the right attached garage is being removed and rebuilt cavity block and brick. the wall between the two will stay.

hope that makes things clearer.
cheers.

existing kitchen extension and attached garage

existing kitchen extension and attached garage

• turnpike
• 17 Jan 2010
• 1

proposed new pitched roof over kitchen extension and new garage

new roof over kitch ext and new garage

• turnpike
• 17 Jan 2010
• 1

 

[Framer]

it depends what the current pitch is now and what might be effected by taking it higher

on your drawing you have done a lower pitch for the new roof and that may be the best way to go assuming its still a steep enough pitch

it is probably easier to just get ne trusses made than to try and patch onto the old roof, there would be no saving in time or money in keeping the old one

 

[turnpike]

Hi Framer,

Yeah I've lowered the pitch in the drawing. If it stays as it is, it would overlap a bit the bathroom window.

What ever it takes to have the job done properly I will do, but just wondering about avoiding upheaval in the kitchen and also already had one or two suggestions along the lines of leaving the existing rafters/joists and adding to them to make the roof wider and higher.

The idea of keeping the same pitch and just adding to the existing joists and rafters sounds a bit dodgy to me. Not that I know anything about it.

 

[noseall]

What tiles do you intend putting on the new roof?

 

[turnpike]

noseall: rosemary tiles. thats what it is now. is it the weight you are wondering about?

i think i understand i bit better now. thanks all. i guess you can build a new roof entirely or just in part. the issue is if it's built correctly whicever method is used.

it's quite hard to describe without seeing it so i'll ask a few more questions of builders giving quotes and try to get a clear picture of how they propose to maintain structural strength.

it would be quite good i think if its an entirely new roof except it'd be very handy if the existing joists are left alone and new ones put inbetween them. simply to avoid me having to replaster the ceiling.

 

[noseall]

Plain tiles (rosemary) should be used on pitches no less than 35 degrees.

 

[Framer]

roof trusses are the way to go from what you have said
you may need to temporarily prop your kitchen ceiling while the trusses go on but these could go along side your existing ceiling joists and be stitched to them , this will then hold your ceiling up and should cause minimal damage, maybe the odd crack as long as you can beat the weather