Which ceiling joists to use?

[thedeadzeds]

Hi All,

I wonder if you can help please. I am currently building a separate stud room within my garage. The structure does not touch any of the walls or ceiling joists. The dimensions are as follows:

12 foot long by 8.5 feet wide and the height is 6 foot 9 inches. So essentially there is currently 4 stud walls with no ceiling as present. All walls are made from 2x4’s and covered with 15mm Soundbloc on the inside only.

I have yet to add the ceiling beams as I need to know what beams to use. The ceiling beams will be spanning the 8.5 wide studs and they need to support 2 layers of 15mm Soundbloc on the inside only (no weight on the outside) which will be filled with 100mm Rockwool. According the website, the weight of the Soundbloc is 12.6 Weight (kg/m²) which I think is roughly 43kg per sheet. So pretty heavy

I was thinking of using 2x7’s 16 oc but not sure if I need 2x8’s oc.

Many thanks
Craig

 

[tony1851]

2x7s will be fine.

 

[thedeadzeds]

2x7s will be fine.

thank very much, a local surveyor was going to charge me £220 as he said he would need to do some tricky calculations due to the fact that I was using heavy soundbloc. You've saved me time and money....very much appreciated

 

[thedeadzeds]

sorry to post again Tony, I'm just wondering due to height restrictions in the garage would there be any shorter timber I could use for example 3 x 5's 16 on centre or do they always have to be something by 2?

thanks

 

[RonnyRaygun]

tricky calculations

 

[tony1851]

tricky calculations

+1