What size rafters for a garage roof?

Question

the garage is 24foot by 12 foot,45 degree pitch and will be carrying concrete roof tiles

Answer 1

I am assuming your rafters will be spanning 12' or 1/2 of the 24' width.  If so, here goes..........With a 50 lb/psf live load and a 20 lb/psf dead load and a 12/12 pitch or 45 degrees, your rafter length would be just under 17'.  At 16" o.c. a Southern Yellow Pine #2 2x12 will span the distance.

Answer 2

6X2, 12 on center.  Concrete is heavy

Answer 3

2x6" in a truss configuration on 16" c

Answer 4

it depends on where you live. there are different codes based on snow loads. it's best to check with your local bulding department, but you could call a local building supply center (lowes, home depot etc...)

Answer 5

I think the answer that someone else gave is what I would say too .    (  It's best to check with your local bulding department  ) .

Answer 6

5 by 2 at 14" centres.

Answer 7

Several things come into play here.  will you ever want to extend upwards? or will the roof live out its life as nothing other than a roof.  take number 1 first - 9 inches x 2.  for number 2 you will need to measure the span in feet and say you get ten feet then the beams will need ten inches minimum in section so you will need 2 inch x 5.  Never come down from this as a nine foot span would still need 2 x 5 you need to set them apart so you get a beam right where you get a join in the covering material, so a 4 foot sheet would need beams at 16 inch centers.  check the sheet sizes carefully as these silly metric sheets often come out at 4 foot and a bit.  Several sheets will give you several bits so before long you will miss the beams with the sheet edges.  Sorry I can't give this to you in metric but I refused to convert and stuck things out until my retirement.  Dont forget to add some firring pieces on top of the beams to give you a fall for allowing water to run off the roof.  All tricky stuff for a noneprofessional... you could just ask the local building inspector who will tell you in detail what is needed......................  Good luck with the job, don't forget to fasten any lighting cables onto the side of the beams and if you fit a ceiling the cabling is already out of your way.  fix it half way up the beam to keep it as far away from nails as possible.  

Professionals don't use the word beams but call them joists.

Sorry I have given you the needs for a flat roof, If it isn't shown on your plan, go to the building inspector for any and all advice.  (I didn't fully read the question before I spouted out my answer.) ................