Help building a roof please

[Jaygray9093]

Hello,

First time building a roof for my greenhouse. Fairly competent.

Ill be using 6x2 for the rafters with one 6x2 as the apex.

The base will be 7ft and the hight will be 2ft. Very shallow I know, but it's only for a greenhouse.

Can anyone help with with the calculation? I think the runs will be 4ft, is that correct?

What angle should I cut each corner at please?

Thank you

 

[blup]

Roughly 30 degrees and 60 degrees bottom and top respectively. Scribing it is most accurate, just overlap the joists, clamp together, measure and allow for the ridge.

 

[Jaygray9093]

That makes sense. Thanks blup

 

[noseall]

Hello,

First time building a roof for my greenhouse. Fairly competent.

Ill be using 6x2 for the rafters with one 6x2 as the apex.

The base will be 7ft and the hight will be 2ft. Very shallow I know, but it's only for a greenhouse.

Can anyone help with with the calculation? I think the runs will be 4ft, is that correct?

What angle should I cut each corner at please?

Thank you

The roof will be 29 degrees. With those measurements the rafter length will be roughly 1277mm (4'- 2, 1/4") long, without overhang. I'd use a 7" x 2" for the ridge board as you need to collect the whole of the plumb cut.

29 degree plumb cut 61 degree seat cut. However 30/60 would make more sense. I'd have some rafter overhang too.

 

[cdbe]

I'm rubbish at geometry, for a greenhouse I'd fit wall plate and ridge board, hold a rafter on the end where I wanted it and mark top cut and birdsmouth, cut it and use as template for the rest.

6x2 is massive - check a rafter span table.

 

[Harry Bloomfield]

Ill be using 6x2 for the rafters with one 6x2 as the apex.

4x2 should I think, still be more than adequate.

 

[noseall]

4x2 should I think, still be more than adequate.

It’s a greenhouse lol. 3” x 2” or just take your pick.