Please help compare the soundproofing of my walls and roof?

Wurlitzer · Post by **Wurlitzer** » Thu Dec 08, 2005 8:04 am

OK, so my previous post about how to get a roof's TL up to par with that of its walls died rather prematurely, maybe because of a certain unfocused verbosity as I groped my way through the process while posting.

I've since been forced to act pretty quickly and have ended up with a roof design that is most of the way to being built.

So I return to the question - how much weaker will the soundproofing of my roof be to that of my walls? But this time with specifics. Note that this is about the outer leaf of my building only - there will be a room within the room, but that's another story.

WALLS:

100mm high density concrete block, rendered and painted.
(90mm two-ply door with MLV in the middle and compression seals. No window).

ROOF (top down):

Three layer felt system, c. 10mm total. (Top two layers bitumen and mineral based torched on. Bottom layer lighter for airation).
18mm OSB
2mm 5kg/m2 MLV
18mm MDF
12mm MDF
150mm timber beams, spaced 40cm apart with rockwool insulation between.

The roof to be completely sealed at the sides to the building structure.

I understand the STC of my block wall, after rendering and painting, will be somewhere between 45-50. I presume the roof will be somewhat less than this, but how much less?

Thanks.

Post by **sharward** » Thu Dec 08, 2005 8:56 am

I don't think your thread died -- but I think it took a nap. Sometimes it takes a few days for those with the most expertise to respond. Steve has a hellish schedule with two 12-hour days on graveyards (our way of saying "the night shift"), then a couple of days off, then two 12-hour days during daylight hours, then a couple of days off. Having worked a graveyard shift years ago, I can tell you it's tough, and even tougher if you're bouncing back and forth from nights to days... So his "bursts" of activity on the site coincide with his days off and consciousness states. You'll just need to be a little patient, and you can bump or PM him if a week or so goes by and you don't get a response.

That's my take -- he's of course welcome to correct or amend accordingly!

--Keith

Wurlitzer · Post by **Wurlitzer** » Thu Dec 08, 2005 9:41 am

Oh don't get me wrong. I wasn't blaming anyone but myself. The expertise and help offered here is amazing and it's incredibly generous of people like Steve to help out for free.

But looking over the thread, I just felt that it had become rather meandering, and it might be hard - especially for someone in a hurry - to be clear about the point of it. A lot of the solutions I was pondering have been made redundant by the recent progress in building works and attendant decisions that have been taken, so I thought it would make more sense to start a new thread on the basis of where I'm at now, with a very clear question that needs answering.

I'm having trouble finding TL figures for materials like OSB, MDF and roofing felt. And I'm also unsure how the TL of all the different materials adds up to the total result. If anyone can help, that'd be dandy.

knightfly · Post by **knightfly** » Thu Dec 08, 2005 2:38 pm

Check your other thread... Steve

Post by **sharward** » Fri Dec 09, 2005 1:33 am

Wurlitzer wrote:Oh don't get me wrong. I wasn't blaming anyone but myself. The expertise and help offered here is amazing and it's incredibly generous of people like Steve to help out for free.

No worries.

I'm an expert at meandering!