Flat roof sound deadening

[i_am_fubar]

Building a workshop with block walls and a flat roof.

Roof is 3m span with feathered 2x10s on 600mm centers. 18mm OSB, 50-100mm PUR, 18mm OSB. Joists are exposed for storage.

I am aware of how loud rain could be, but also tool noise escaping. I was wondering if there is an additional acoustic layer I could add, like paving slabs or tiles that would help.

Any thoughts?

 

[Deluks]

You could do cold roof, with the densest rockwool you can get hold of. If you've got 300mm to play with then that could be 250mm insulation which will dampen sound better than pur.

Double plasterboard and use ceiling hooks for storage (what are you storing?)

Also, windows, doors and walls need to be considered. Dense concrete blocks, double glazed everything, and tightly fitting.

Having open ceiling joists is going to limit your options. You don't really need 2x10" for that span anyway, maybe you could rethink the design?

 

[i_am_fubar]

The 2x10s will be feathered to give my roof slope. They exist 2.4m and up to give me more storage. Warm deck is preferred as I have no soffit vent space. 600mm centers is so I can fit my 600x600 panel lights.

Storing ropes, cables, material lengths... Etc

Would also add that I'm making the structure from dense concrete. Only one end will be glazed and it'll be airtight with an active ventilation system

 

[foxhole]

Wear ear protectors.

 

[Deluks]

All you can really do is add more mass to the roof.
Attempting to 'dampen down' the sound by adding slabs may or may not work depending on the sound source.
It is often a benefit to use differing materials, so switching your first osb layer for plywood might attenuate the noise slightly better.
You could also incorporate cement board into the roof build up, glue it to the underside of the deck to add mass. Or add a layer underneath the insulation.
If felting then add a layer of chippings on top.

 

[i_am_fubar]

Ohhhh, cement board! Yes! That's the ticket cheers!