pitch roof wall plate

[colw1]

hi im building a double pitch roof with gable ends and im going to use 6x2 timber due to the 4.9m span , the roof angle is shallow at approx 20 deg which is going to be tiled . What I need to know is firstly what size wall plate that is needed would this be ok to put this on the outside edge of the solid wall and also do I need to bed this in on mortar because the wall is perfectly level so can it just be fixed directly to the nine inch blocks
Finally this building is a workshop in the garden

 

[masona]

4"x2" is the norm and having a wallplate tie the roofing section together

Make sure you pick all straight one if you're having it delivered

 

[markie]

4"x2" is the norm and having a wallplate tie the roofing section together

Make sure you pick all straight one if you're having it delivered

If he's having them delivered how can he pick all straight one's, if it's like the companys we use and you request them to deliver, they normally give you a few bent one's just to get rid.

 

[noseall]

at 20deg pitch, 6"x2" rafters are nowhere near enough for a 4.9m span. do you intend putting a purlin at midspan?

 

[freddiemercurystwin]

at 20deg pitch, 6"x2" rafters are nowhere near enough for a 4.9m span. do you intend putting a purlin at midspan?

Also at that pitch you need to check your tiles will work (windlift and waterproofing). Most coverings won't go down that shallow, not even slate, some interlocking ones do I think. You'll kiss goodbye to any warranty if the manufacturer doesn't recommend that pitch.

 

[masona]

4"x2" is the norm and having a wallplate tie the roofing section together

Make sure you pick all straight one if you're having it delivered

If he's having them delivered how can he pick all straight one's,

Easy, you pop down to the timber yard and mark them with the felt tip pen with "sold to markie". If any of timber yard send me banana timber I refused to have them, it's simple really. The timber yard know me well enough now to keep me happy

 

[marksson]

Some concrete interlocking tiles go to 17.5deg granular and 15deg smooth, or there are a couple of slate looking interlocking tiles that go to 12.5deg.
Def need a purlin in that scenario.

 

[^woody^]

6 x 2 rafters at 20 deg will span 2.6 m to the ridge, and well within the unsupported span maximum of 3.78m at 400 centres or 3.3 at 600 centres.

In fact 5 x 2 could be used.

There is no problem with fitting the wall plate to the external, but then it may be difficult to strap down. Also it should be protected from getting damp direct or via the external leaf.

It should be bedded on mortar