Garden shed conversion

[pricey05]

Hi everybody

I am about to embark on a project to turn a standard workshop shed into a space in which I can practice on my drum kit and hopefully record them too from time to time using a DAW system with a simple near field monitor setup.

The shed is 12’ x 14’ with an apex roof. The gable end is 12’. It’s going to be sat on a paved area behind my house. Neighbours are approx 10-20 metres away in all directions.

I am under no illusion that this is going to require a lot of work to get this space relatively isolated from the environment and usable for what I want to do in it. I also don’t have a big budget so I’m trying to be clever about the design here.

I want to create a two leaf system (MAM) incorporating the sheds outer layer (12mm shiplap, almost negligible in terms of sound isolation).

I would essentially ‘beef up’ the sheds outer shiplap layer by adding layers of drywall portions in-between the timber frame on the walls and ceiling. This would become the first leaf. Some vapour barrier in here somewhere?? Then I go about building a secondary stud work frame with 3 layers of drywall for the interior walls and ceiling. Mineral wool in-between the two leaves Caulking would be used to seal gaps at joints etc.

Unfortunately because this is typical garden shed the outer leaf is attached to the floor structure (simple runners with tongue and groove timber floor). My stud work for the interior leaf would be coupled so structural and airborne resonances would transfer through the floor and into the stud work and the outer leaf. I want to reduce this effect on a budget and without reducing too much ceiling height.

Initial idea for floor is:

- create another floor frame with a hardboard top which sits onto original floor and is not in contact with the interior walls except for caulking sealant. The hardboard top (ply or OSB) would have cheap concrete paving slaps laid on top with some lino laid over that. This should create stiff surface for the drums and reduce travelling resonances from the sound source to the interior and exterior leaves. The air gap created from the new floor frame would be filled with mineral wool for some thermal insulation.

Ventilation would be achieved with baffled ducts and I would use an oil filled radiator for heating in cooler climes. I’m thinking about HVAC and I’ve read plenty about the surrounding design issues- lots to think about there. Electrics are another issue and will be installed properly with minimal protrusions through walls so basically surface mounted.

I am making a new outer door for the shed and another door will be hung in the secondary stud work system. Both will be using seals etc.

But for now I’m just concentrating on keeping the sound in and am interested in what you good people think of my ideas here…

I’ve attached a simple sketch illustrating my very rough plan.

[pricey05]

To be more specific I will say that I have about £1500ish for isolating the shed.

[xSpace]

Is this a shed you are building...have already built or is something you are going to have moved to your home?

[pricey05]

I have ordered the shed already. It will come in a flat pack type kit for me and my friend to assemble. I went for this option really for ease and just so I could concentrate more on soundproofing. The main wall panels will be assembled already with stud work style framing with the cladding attached and with some kind of breathable membrane on the inside. I'm now thinking I should leave a small air gap and build my layers of plasterboard on top of the shed framework on the inside, seal it up and then build my stud work for the inner leaf. This would technically make the shed cladding a third leaf but considering it's only 12mm thick I wouldn't think it would act as third leaf in reality anyway??

The more I think about it now I may have been able to design a shed from scratch focusing on sound isolation from the ground up but I'm just going to have to work with what I've got now...

[Soundman2020]

Hi "pricey05", and welcome!

I am about to embark on a project to turn a standard workshop shed into a space in which I can practice on my drum kit

I would not go down that path if I were you. A typical shed is way to flimsy to be usable for what you have in mind, which is where Brien's question was going too, I'm sure.

I also don’t have a big budget so I’m trying to be clever about the design here.

Please don't take this the wrong way, but trying to use a prefab shed as a drum isolation booth is not very clever! Drums are loud, and put out most of their energy in low frequencies. Low frequencies are the hardest of all to isolate, and doing that requires a lot of mass, careful air-tight seals, and lots of damping in the wall cavities. Sheds have none of those.

I want to create a two leaf system (MAM) incorporating the sheds outer layer (12mm shiplap, almost negligible in terms of sound isolation).

Right. Meaning that your inner-leaf will have to be extremely massive (heavy), and your air gap will have to be very large.

Some vapour barrier in here somewhere??

Yes, in the same place that all vapor barriers go in your climate, which won't be the outer leaf! You might also need a water barrier, which would go on the outer leaf, but you won't be able to put one in there, if the walls come pre-assembled...

Unfortunately because this is typical garden shed the outer leaf is attached to the floor structure (simple runners with tongue and groove timber floor).

You'll have to get rid of that: no use at all. Just take it out, and get down to the bare concrete of your slab.

My stud work for the interior leaf would be coupled

Unless you get rid of that useless floor, you cannot have any inner leaf! That "floor" would be totally unusable to support the huge load of the inner leaf that you would need. No chance at all.

- create another floor frame with a hardboard top which sits onto original floor and is not in contact with the interior walls except for caulking sealant. The hardboard top (ply or OSB) would have cheap concrete paving slaps laid on top with some lino laid over that.

Did you check that with a structural engineer? I don't see any way that a "simple runners with tongue and groove timber floor" would be able to take anywhere near that amount of load, let alone the huge additional load of the walls, plus the equally huge load of the inner-leaf ceiling, plus the load of your gear, instruments, people, furniture...

This should create stiff surface for the drums and reduce travelling resonances from the sound source to the interior and exterior leaves.

Actually, it wouldn't do either: your concrete paving slabs would not create a stiff floor, and neither would it be decoupled from the underlying original floor, so impact noise would get through loud and clear, as would most of the low end of your drum kit. I'm not sure what you mean by "traveling resonance"? It's not a term I'm familiar with. I googled it, but only got hits for a travel and tourism company... Maybe you could explain what you mean by that?

Ventilation would be achieved with baffled ducts and I would use an oil filled radiator for heating in cooler climes.

How will you deal with the humidity issue?

But for now I’m just concentrating on keeping the sound in and am interested in what you good people think of my ideas here…

You haven't mentioned anything at all about the outer-leaf roof or the inner-leaf ceiling, which constitute the final "side" of the room and is critical for "keeping sound in". How are you going to beef up the existing roof sufficiently so that it can act as a usable outer leaf? And what structural modifications will that require to the existing shed walls and roof, in order to be able to support the huge extra mass? Have you spoken to a structural engineer about that, and what did he suggest? The amount of mass you'll be adding up there to successfully isolate drums will be similar to the weight of a small car, so if you have not spoken to the structural engineer about that yet, then mentioning "as heavy as a car" will give him an idea of how much extra support he'll have to design into your shed walls, to be able to handle support that safely.

To be more specific I will say that I have about £1500ish for isolating the shed.

I don't mean to be harsh, but I think you are missing a zero off the end of that. You have a flimsy pre-fab shed with 168 square feet of floor space, and you are proposing to convert it a fully isolated drum studio with lighting, heating, A/C, isolation, treatment and decoration for less than £8.92 per square foot? Sorry, but that isn't going to happen. That would be about enough to do the final finish floor and one door, and that's about it.

I'd suggest that you seriously re-think either your budget, or your goals, or both. You can't get that amount of isolation in a tiny budget, so either you need to increase the budget drastically, or greatly reduce your goal of being able to play drums in there without it being a problem for your neighbors or family.

Don't get me wrong! I'm not saying you should give up! There are things you can do with £1500 to slightly improve the transmission loss, but it won't get you anywhere close to fully isolating for drums. So I'm not trying to discourage you: just to bring to your attention the realities of studio isolation vs. money.

- Stuart -

[xSpace]

Ok, on order...kinda the cart before the horse but let's see where this goes. Everything that Stuart said was kinda part of what I wanted to address but I had to know the condition of this shed.

So you have an asphalt driveway or pad that you want to set it on, correct...it isn't concrete is what I am reading. Like Stu mentioned...that floor is useless and your build up of it is even more uselesser:) You have a light membrane that will vibrate just like it is part of the drum set, especially with the added framing and additional sheathing/tile pieces.

Obviously removing the floor completely and using the Earth damped mass is the way to go. Problem is, if this is in fact asphalt, it will wick moisture and present problems with condensation that can rot and cause health isses...mostly rot at this point.

If the situation where so, you might could dig/form and pour a concrete slab and place the shed directly ono that....without the wood framed floor. If this isn't possible then, again, add mass directly to the existing floor.

I will leave this above to you so you can correct me as needs be.

Now, the walls. You are looking at this the wrong way. What would be better would be to remove the siding that comes with the shed and add an exterior gypsum sheathing directly back to the studs. You could add two layers if so you are so inclined but that is up to you. Then I would look up http://www.greengluecompany.com/sites/d ... nnel_1.pdf rather than additional interior framing.

To get the highest amount of isolation possible with this situation you should add extra sheathing to the roof as well, before the finish material is installed.

[pricey05]

Thank you Stuart and xSpace for your replies. Yep, i know...on order ermmmmm yeahhh . I just really want somewhere that I can put some practice in without having to drive to a rehearsal studio every single time and also not have to go down the route of building a brick structure. I work full time so my evenings are limited and the weekends are my other opportunity.

I realise that I am starting with a structure that isn't designed to withstand large amounts of weight strapped to it. I am going to have to add extra bracing and supports where necessary on the ceiling and wall structure to be able to safely hang the gypsum board up for the added mass. I will try and speak to someone knowledgable about this area of the design.

I am not going to use the shed floor any more after your recommendations. So I am going to think about how I'm mounting the shed on the slab paved area I already have. And what I will build the inner structure onto (maybe onto a secondary layer of concrete slabs directly placed on the paved area and a damp proof course somewhere there). This all needs more thought though.

Well, at the moment I am going to carry thinking about all of your suggestions and advice and I'll get back to you guys again soon!

Sam