Sticking roofing felt to the INSIDE of corrugated sheet

[Deluks]

I'm currently in the process of building a music rehearsal room in the garage, one snag I've hit is that the existing corrugated asbestos type roof is too thin to keep sound in. I'm actually building a new false ceiling underneath it, but I still need to beef up the density of the outer roof for half-decent sound insulation.
Replacing it is not an option due to budget constraints, so I'm considering sticking roofing felt (bitumen type?) on the underside. Making sure it follows the contour of the ridges.

A fiddly p.i.t.a. job I'm sure but whats the best material to use? and more importantly, how do I make it stick?

Wickes sell a bituminous roofing felt adhesive, does anyone know if it's particularly tacky, or is it just runny stuff that has to dry before it properly bonds?

Cheers
Deluks[/i]

 

[Thermo]

youd be better spending the money on thicker insulation under the roof, it will be less hassle and more effective

 

[nstreet]

All well and good but the door will need doing also.

For the roof, a false ceiling would be best, constructed from battens and platerboard, with the insulation above the board. It will also keep you warm in the winter.

Hope you are on good terms with your neighbours.

 

[Deluks]

Thanks for the advice guys, I've pretty much got everything planned. I'm using mdf and plasterboard for the walls and false ceiling (rockwool between that and outer roof), and using a double door and double glazed window on 2 separate frames. The room should be pretty much soundproof apart from that outer roof, which could resonate or 'hum' unless I increase the mass somehow.
I intend at a later date to use corugated bitumen sheets fixed on the top of the roof, but I need to everything I can on the underside before putting the false ceiling in, as I don't want to have to take it all down and retrofit a solution once it's built.

Bitumen is very good for sound attenuation as it's quite dense, but what roofing products are available that you think will suit my needs? Can you get the bitumen sheet type stuff without the little grey bits of grit stuck to it, as most of my neighbours shed roofs seem to have?

 

[Nige F]

Car underseal? painted on- cheap.

 

[Deluks]

Car underseal? painted on- cheap.

Not a bad idea, I've already painted the underside with bitumen paint, but it doesn't go on that thick and is rather runny. How does car underseal work? Is it very gloopy and can it be 'built up'

Poundland sell the stuff for a pound Maybe I'll buy a tin and see?

On the other hand, Wickes sell shed felt in 5 square metre rolls for about a fiver, and the adhesive for another fiver on top of that, if I were to remove the roof sheets, flip em over on the lawn and apply the felt that way, does that seem like an easy job?

 

[Nige F]

Yes Underseal can be built up...it used to hide a multitude of sins . Not so sure about the felt tho` it may not stay underneath as the adhesive gets hot from the sun on the roof. Also taking sheets off and replacing may break them.

 

[oilman]

What sort of music are you going to be playing? You won't stop low frequencies unless the walls and roof are massive, and/or the walls and roof are lined with the same stuff that's used for anechoic chambers.

Corrugated cement sheets are designed to be used with airflow on both sides, if you seal the underside you might generate problems.

 

[Deluks]

Will be playing loud music Including drums so I will need all the help I can get!

I will be building a 6x2 joist ceiling under the existing roof (not touching it) and putting 36mm of mdf and a layer of 12mm plasterboard up between the joists. This is my first defence against low frequencies but the corrugated roof is my second, and it will be ****-poor!

The roof is mainly asbestos concrete type stuff with a couple of the more modern eternit sheets.

What potential probs could I encounter by sealing the underside of the sheets?

Does anyone have any better ideas to increase the mass on my roof? (Replacing roof not an option)

 

[gazza2]

would think that two sheets of celotex or similar would do the job better, if required stick a layer of rockwool in between, remember that if they solid substances touch, the vibration ( sound) will transfer from one to the other) the aim is to deaden, and reduce the vibration, so a solution with
soundproofing, air gap , sound proofing, airgap, soundrpoofing will be your best bet.

I would try 2" celotex, 1"airgap, 1" rockwall, 1" airgap, 1"celotex.

what does everyone else think ?

 

[oilman]

You need to do some searching the web for "soundproofing". You will need a damn near sealed room or the tinyest gap will let sound out. You will suffocate unless you have special ventilation to compensate, you will need to build the room clear of the ground, otherwise the sound will get out that way.

WHY do you feel the NEED to have LOUD music? It seems like the "musicians" version of gadget collecting, or "mine's bigger than yours".

 

[Deluks]

WHY do you feel the NEED to have LOUD music? It seems like the "musicians" version of gadget collecting, or "mine's bigger than yours".

ROFL!!!!

I completely agree! but try telling that to a drummer!

I've done literally months of research into soundproofing. I'll be building a heavy ceiling underneath that roof which will not be in contact with it, or the walls for that matter.

For proper soundproofing you need two heavy barriers, with just one airgap in between. I already have one heavy barrier planned, with the mdf and plasterboard ceiling, it's just that the asbestos roof is my second barrier, and that will probably resonate unless mass is added.

I will be using rockwool slabs in between, which will dampen but not prevent bass sounds (ie: kick drum) from escaping.

Celotex/kingspan and polystyrene etc. is also useless for soundproofing, well for music purposes anyway. I am suprised that no-ones mentioned eggboxes yet though.

Would it be possible to concrete the outside of the roof flat? or is that a bit cloud cuckoo?

Cheers for all replies so far

 

[Deluks]

OK, started today on the first of many!

Yep, it was a messy p.i.t.a. but it's the only solution I could come up with on a budget.

The plan is to:

1) Remove each sheet (carefully!) from the roof, lay it on the lawn bottom up.

2) Fill the corrugations with expanding foam.

3) Wait for it to semi-cure, then flatten it so it's level.

4) Apply bituminous felt adhesive (£4.55 in Wickes) to the edges and tops of ridges.

5) Measure, cut and lay a sheet of roofing felt (shed felt, £4.98 a roll in Wickes) on top, level with the tops of the ridges.

6) Leave to dry and replace back on roof.

It all sounds a bit mad I know, but will definitely dampen the roof against bass vibrations, not totally but will still be a massive improvement on leaving it as it is.

Incidentally does anyone know how long this bitumen adhesive stuff takes to dry? Does it dry like paint or stay flexible. I don't want the felt to fall off from the ceiling.

Cheers
Del

 

[masona]

Incidentally does anyone know how long this bitumen adhesive stuff takes to dry? Does it dry like paint or stay flexible.

Depending on the softening point and what grade the bitumen is.

Normally dry very quick but will soften in the heat.

 

[Deluks]

Depending on the softening point and what grade the bitumen is.

No idea tbh, it's wickes own brand in a tin stuff, very thick but the tin gives no extra info.

As long as it goes off eventually.

Cheers
Del