help with roof

[b21playa]

Hi all

Just getting info so I plan the roof build on my shed.

wall to wall it is 4.85m x 5.7m, being built in 6" blocks

What i need to know, is ridge, rafter and wall plate sizes. Ive seen 6x2 in our local yard for £6 for 3.6m lengths. 8x2 4.8m length for £11.

I want the ridge beam going along the short length, so the rafters have a shorten span.

is 6x 2 fine for the rafters, and can this be used for the ridge?
What size should wall plate be?
Do i need restraint straps?

Thanks

 

[noseall]

4"x 2" would be ok for the wall plate though i prefer 4" x 3" (tanalised).

Holding down straps will be useful every 2m, restraint straps will be needed on a masonry gable end.

What pitch do you intend setting the roof?

You want the ridge beam across the longest run to give the shortest rafter length.
I.e. 4850 divided by 2 gives a 2425 run. At say 25 degrees this will equate to a 2668mm long rafter. A 6"x2" will eat it.

You will also need joists or collars to stabilize the roof. 4.8m is a fair span.

What ever you use for the rafters the ridge beam needs to be deeper, but not necessarily the same thickness. This is so the whole ridge-plumb cut is seated on the ridge beam.

 

[b21playa]

4"x 2" would be ok for the wall plate though i prefer 4" x 3" (tanalised).

Holding down straps will be useful every 2m, restraint straps will be needed on a masonry gable end.

What pitch do you intend setting the roof?

You want the ridge beam across the longest run to give the shortest rafter length.
I.e. 4850 divided by 2 gives a 2425 run. At say 25 degrees this will equate to a 2668mm long rafter. A 6"x2" will eat it.

You will also need joists or collars to stabilize the roof. 4.8m is a fair span.

What ever you use for the rafters the ridge beam needs to be deeper, but not necessarily the same thickness. This is so the whole ridge-plumb cut is seated on the ridge beam.

I have concrete tiles, so thought of 25deg

I I put the ridge along the longest part, the roof doesnt look nice, plus I would need a 6m ridge beam.

I thought 8x2 for the ridge beam, 6x2 for the rafters.

As its only a shed, collars rather then joists.

Do I face-nail rafters to ridge beam?
Also do I have to birdsmouth the rafter or can I use truss clips?

 

[noseall]

I have concrete tiles, so thought of 25deg

Anything from 25-45 degrees is within the realms of conc' tiles though 25 degrees is more sheddish.

I I put the ridge along the longest part, the roof doesnt look nice, plus I would need a 6m ridge beam.

A ridge beam can be joined.

I thought 8x2 for the ridge beam, 6x2 for the rafters.

Sounds good.

As its only a shed, collars rather then joists.

Cool.

Do I face-nail rafters to ridge beam?

Face nail, eh? You just bank a spike through the top and skew one each side.

Also do I have to birdsmouth the rafter or can I use truss clips?

Truss clips are only suitable for trusses, yes you need to b/m over the wall plate.

 

[b21playa]

All sounds good

Just need to look into how to birdsmouth correctly and how to cut rafter overhang correctly so to put facia board

 

[b21playa]

anyone got link to a guide I can follow for help?

 

[freddiemercurystwin]

http://books.google.co.uk/books?id=...=X&oi=book_result&resnum=10&ct=result#PPA5,M1

 

[b21playa]

http://books.google.co.uk/books?id=0SCGVmOUh1kC&pg=PA204&lpg=PA204&dq=dormer+roof+construction+guide&source=bl&ots=wgppwE5liA&sig=ccq-ijXex6X7J0Yt1zRk7AP6Qas&hl=en&ei=8ouuSZOkKJC0jAec_ZGhBg&sa=X&oi=book_result&resnum=10&ct=result#PPA5,M1

Many thanks