How to create overhang over garage doors when running posi joists across walls?

[theflyingpig]

I'm planning on using 6m long posi joists across the walls to create roof structure on a double garage... It's to have a flat roof, with slope created from tapered pir.

Any ideas as to how to form an overhang over door? Other than literally hanging a bit of frame work off the deck? I can't irnvusage there is much to fix to on a posi joist? (never used em before)....

Thanks!

 

[noseall]

I'm planning on using 6m long posi joists across the walls to create roof structure on a double garage... It's to have a flat roof, with slope created from tapered pir.

Any ideas as to how to form an overhang over door? Other than literally hanging a bit of frame work off the deck? I can't irnvusage there is much to fix to on a posi joist? (never used em before)....

Thanks!

In the absence of any specific design from your supplier(?) - keep the last joist back a wee bit from the inner face of the wall. Fix a same depth timber to the face of the posi, the run timbers off joist hangers to the outside.

 

[theflyingpig]

In the absence of any specific design from your supplier(?) - keep the last joist back a wee bit from the inner face of the wall. Fix a same depth timber to the face of the posi, the run timbers off joist hangers to the outside.

Good idea. Thanks

 

[theflyingpig]

Right! Quote in for the tapered insulation..... Over 2 k for 36 square metres of tapered insulation... And that would be tapering from 130 at the high end to just 30mm...

So, scrap that idea.... I can get furring strips to create the fall from 200mm to nothing for about 500 quid, or cut them myself with a jigsaw...
That way I could sandwich 100mm of celotex between an 18mm osb deck and 12mm top layer to take the epdm
But, here's the dilemma.... The way I see it the joists have to run from wall to wall, but if the roof slopes from one side to the other the visible front elevation will look silly....
Whats my options? A steel across the front I suppose, but that would mean block columns to support when the whole plan was to build out of just timber once above dpc.....

Ideas? Thanks!

 

[noseall]

or cut them myself with a jigsaw...

Massive lol. Please video it.

 

[noseall]

Right! Quote in for the tapered insulation..... Over 2 k for 36 square metres of tapered insulation... And that would be tapering from 130 at the high end to just 30mm...

So, scrap that idea.... I can get furring strips to create the fall from 200mm to nothing for about 500 quid, or cut them myself with a jigsaw...
That way I could sandwich 100mm of celotex between an 18mm osb deck and 12mm top layer to take the epdm
But, here's the dilemma.... The way I see it the joists have to run from wall to wall, but if the roof slopes from one side to the other the visible front elevation will look silly....
Whats my options? A steel across the front I suppose, but that would mean block columns to support when the whole plan was to build out of just timber once above dpc.....

Ideas? Thanks!

Add varying thicknesses of timber to the tops of the joists to create a fall. Use a line. You'll need some pretty thin material in order to be able to pack accurately.

 

[theflyingpig]

Massive lol. Please video it.

Yeah, I'd be there a while!

 

[theflyingpig]

Add varying thicknesses of timber to the tops of the joists to create a fall. Use a line. You'll need some pretty thin material in order to be able to pack accurately.

Hah. Good plan. Though I suppose furrings run perpendicular to the joists would do same thing, but look rubbish from the underside.....

 

[cdbe]

£500! I never understood why people don't just set one end of the joist higher than the other end. If a level ceiling is required some cheap CLS timber can be hung below to carry it. Personally I think 18mm osb is overkill for this roof type - I know it's standard for a normal roof deck but a 9mm/100mm+ of PIR/9mm sandwich would be fine. 30mm of insulation anywhere seems pointless to me.

 

[theflyingpig]

£500! I never understood why people don't just set one end of the joist higher than the other end. If a level ceiling is required some cheap CLS timber can be hung below to carry it. Personally I think 18mm osb is overkill for this roof type - I know it's standard for a normal roof deck but a 9mm/100mm+ of PIR/9mm sandwich would be fine. 30mm of insulation anywhere seems pointless to me.

I appreciate your points here.... It would certainly be easier to create the fall with the actual joists... But.... when have you ever set something out of level or plumb and not regretted it later?? Yes, could level out ceiling later, but I'd not enjoy it!

 

[theflyingpig]

Agreed re 30mm of insulation, pointless. I won't be doing the tapered insulation.

 

[theflyingpig]

In the absence of any specific design from your supplier(?) - keep the last joist back a wee bit from the inner face of the wall. Fix a same depth timber to the face of the posi, the run timbers off joist hangers to the outside.

Precisely what posi joist supplier has suggested

 

[theflyingpig]

So OK with front overhang detail. Now thinking about fascias... How much will roof need to be past wall to allow for cladding and fascia?

 

[noseall]

So OK with front overhang detail. Now thinking about fascias... How much will roof need to be past wall to allow for cladding and fascia?

The internal lip of (cap) fascia is 30 - 35mm. What do you mean by cladding? Are you adding material to the external walls?

 

[theflyingpig]

Walls are to be 6*2 timber studs, noggins and metal strap bracing... So yes, likely clad with vertical gravel boards, with battens over joins...
So total cladding depth approx 50mm....