Canopy roof timbers

[gaz_moose]

I want to build a canopy roof like attached.

Ive only ever done flat roofs and this will be tiled with marley double roman concrete.

width will be 9.5m 

 

How do i calculate what size timbers to use? 

Does my paintshop plan look like how they are built?

I intend to put gallow brackets at either end and in the centre. ( the house is like you would draw as a kid with 4 windows and the door in the centre) so i was going to put 2 gallows either side of the door so 4 gallow brackets in total.

 

MY brain says to use 2x4 c16 for everything except the facia board which would be 1". But i dont want the facia boards to be massive so can i use smaller timber?

 

 

[Russell griffiths]

Sort of but not entirely right. 
your terminology is a bit wrong. 
the joist in red is a rafter.

horizontal in blue is a joist 

so red one rafter needs a seat cut at the bottom to either sit on top of the blue one (joist) or fix it to the side of the blue one. 
this will lower your facia height. 
i would also look for a different tile, the double romans are a pain to get the ends looking neat, they also look too big on a small roof. 
go for a small concrete tile. 

[gaz_moose]

So cut the rafter ends like this

 

I was going to use dry verge ends, i know they look a bit naff.

 

Where the rafters meet the wall plate should i stick with birdmouth setup so it sits on top of the wall plate or can i just have the rafter butted up to the wall plate and screw them together? i was going to use 100mm deep timbers for the rafters and figured there wouldn't be much left after id cut the birdmouth.

 

I was going to screw it all together is that ok or should it be nails? (I appreciate this is a basic questing but i know certain things in roofing should be nailed)

 

Interesting point about the tile size. these roofs are common on the houses round here and the ones where the tiles don't match the main roof tiles look odd so my hands are tied.

 

Edited 7 hours ago by gaz_moose

[JohnMo]

Make the rafter long enough to have PV panels in landscape and do the roof in solar panels - if east,south or west facing?  No tiles to faff with.  Choose the panels well and you could get 6 panels on the there.

[Russell griffiths]

27 minutes ago, JohnMo said:

Make the rafter long enough to have PV panels in landscape and do the roof in solar panels - if east,south or west facing?  No tiles to faff with.  Choose the panels well and you could get 6 panels on the there.

Out of 10 how shit would that look. 
probably a 10, maybe even 11 or 12. 
c’mon let’s be sensible we all like to make a bit of free electricity but that is a proper nasty. 

[Russell griffiths]

3 hours ago, gaz_moose said:

So cut the rafter ends like this

 

I was going to use dry verge ends, i know they look a bit naff.

 

Where the rafters meet the wall plate should i stick with birdmouth setup so it sits on top of the wall plate or can i just have the rafter butted up to the wall plate and screw them together? i was going to use 100mm deep timbers for the rafters and figured there wouldn't be much left after id cut the birdmouth.

 

I was going to screw it all together is that ok or should it be nails? (I appreciate this is a basic questing but i know certain things in roofing should be nailed)

 

Interesting point about the tile size. these roofs are common on the houses round here and the ones where the tiles don't match the main roof tiles look odd so my hands are tied.

 

Sort of if you want the facia smaller 

you might have a wall plate running from left to right on top of the gallows brackets that the rafters notch into using a birds mouth cut. 
its hard to tell the drawing needs to be 3 dimensional really. 

[Russell griffiths]

You can buy these all pre made by a truss manufacturer 

just screw a wall plate to the wall and away you go. 

[saveasteading]

Use  treated timber (Tanalised or equivalent) and C24.... the C16  untreated is generally for lightweight internal work, and the cost difference is small.

The element doing most work in your example is the fascia board, as it is supporting multiple rafter and joist ends, and that isn't good.

 

Start with the gallows brackets, then add a timber to the front, bearing on them, then fit the rafters and joists. The fascia is for show and to keep the weather out.

This is a very small structure which is supporting your tiles most of the time, but occasionally will have wind uplift.

Nobody is going to die if it fails, but it is still best to keep it to the logic above.

 

 

[JohnMo]

1 hour ago, Russell griffiths said:

Out of 10 how shit would that look. 
probably a 10, maybe even 11 or 12. 
c’mon let’s be sensible we all like to make a bit of free electricity but that is a proper nasty. 

That's me told - I'll ask for your opinion first next time.

[ETC]

[saveasteading]

Nice looking drawing but fascia is spelt thus, and without the 's' it is a mis-spelling , however common.

 

I'm not clear on what is supporting the 'running bearer' . And although it is stated as 100 deep it scales much less.

Plus there seem to be a lot of those diagonal supports.... a lot of wood on show.

 

It is strange that such a formal looking drawing, which initially inspires confidence, has these, and maybe more, errors.