external door+floor insulation, log cabin garden studio

[Pepeluis]

Hi folks,

my first post on forum though have been reading many past posts and learned a lot.

I am at planning stage of my log cabin style home studio build. I have someone who will be buiding it in my back garden, modest budget of approx £10-12.

Main use is to record original songs/instrumentals for film/tv, have had some good placements up to now with tracks recorded in a more or less cuboid spare room aprox. 3mx3m (terrible dimensions I know!),

Not planning to record drum kit or full band , loudest instruments used are congas/percussion, occasional electric guitar, vocals etc. Monitors are KRK RP5, I don't monitor very loud (sorry don't have db measurements right now).

dimensions-4x5m, max height 2.5m (under UK permitted development rules)

construction- chipboard outer leaf with shiplap cladding then 4x2 inch timber studs with 50mm RW3 insulation in cavities. then 2 layers of 15mm acoustic plasterboard. EPDM roof covering..

window.-aprox. 1mx60cm double glazed.(split into 2 panels, 1 opening) laminated both sides. 6.8mm/16mm/6.8mm. or another option (not sure which is best) is glass config.of 6.4KS/16/6.8Acoustic glass (KS is Pilkington, and Laminate glass is Pilkington Optithon).

https://www.modernupvcwindows.co.uk/win ... 550&v0=600

cost approx. £125

I do understand the isolation problem with windows but prepared to make a compromise to have some natural light.

I have a couple of questions maybe someone could help with.

making a decision about an external door, looking to buy a complete finished doorset with locks pre-installed, Just want something easy for builder to put up without too much extra work. don't want to have to make a door or frame.

option 1- whole glass double glazed upvc door with acoustic glass

https://www.modernupvcwindows.co.uk/upv ... &p0=000400

(laminated both sides. 6.8mm/16mm/6.8mm. or another option is glass config.of 6.4KS/16/6.8Acoustic glass (KS is Pilkington, and Laminate glass is Pilkington Optithon) again unsure which option best. these are options presented by door manufacturer. Price approx £450

option 2-solid composite door

http://www.justdoorsuk.com/composite_do ... hp?ID=1095

Price £425 plus sealing cost . I do understand that a panelled door is not ideal but proving hard to find a flush door I can configure within my budget.. with this option I know I would have to have put in some good seals.

Would appreciate any advice please, my thoughts are that probably the composite door would give better isolation if sealed correctly, the glass door would give more light, acceptable seals but big reflective surface to address, also would need to fit shutters or curtain right away for security reasons, composite door would be easier to add mass to if needed.

I am also deciding on floor config.

There are buiding regs about thermal insulation (will check what is stated) but as I am in UK I will want some thermal insulation in any case. Builder will be putting down a concrete base with waterproof layer (not planning floating floor).

options I am considering..

Option 1- concrete base-2 inch joists-2inch Celotex or similar (would lose some ceiling height)-plywood layer-laminate flooring.

Option 2- Have heard about a concrete mix for a base that incorporates thermal insulation (perlite maybe?)-not sure what this mix is or if it will have strength to support cabin but could save me precious ceiling height.if no further insulation needed. Plywood layer could go on top then laminate flooring.

Main aim is to stay within or close to budget and not overdo things beyond what I am likely to need. Any thoughts much appreciated.

many thanks in advance,
Jose

[Soundman2020]

Hi José, and Welcome!

modest budget of approx £10-12.

Only 12 Pounds? Maybe you missed a few zeroes off there? Assuming that was supposed to be 12,000, even so, it's very much on the low side for a ground-up studio build. Just the HVAC system alone is going to take a large hunk out of that, and excavating/pouring the slab is going to take another large chunk. The owners of studios that I have designed in the UK tell me that the cost seems to work out at around £1,000 to 1,500 per square meter. You mention a footprint of about 20m2, so I would estimate that you'd need a budget of around 20k to 30k, realistically.

I don't monitor very loud (sorry don't have db measurements right now).

Before you can decide on your isolation plan, you need to know how much isolation you need... the only way to do that, is to measure with a meter. So you can't advance much further with you plans until you get that. Maybe that's why your plan so far has no real isolation at all?

dimensions-4x5m, max height 2.5m (under UK permitted development rules)

So this is just going to be a single-room studio? Combined CR and LR? in 20m2, you can't do much more than a single room, realistically. And especially on a very tight budget.

construction- chipboard outer leaf with shiplap cladding

Your thread title says "log cabin garden studio", but I don't see where the logs are in your basic description of the outer leaf. Maybe you could clarify?

then 4x2 inch timber studs with 50mm RW3 insulation in cavities. then 2 layers of 15mm acoustic plasterboard.

So clearly you don't want much isolation at all. I'm wondering why? Are your neighbors and family OK with the sounds you'll be making? Does your local municipality not have restrictions on noise? It just seems strange that you'd go to the trouble and expense of constructing a special studio building in your back yard, but then not isolate it well, acoustically.

window.-aprox. 1mx60cm double glazed.(split into 2 panels, 1 opening) laminated both sides.

OK, now you have me intrigued! Double glazed units that are also laminated? That's unusual. I wasn't even aware that anyone makes such things. Most double glazed windows are just done with ordinary glass. Laminated double glazed units sound rather expensive. Would it not be better / simpler / cheaper to just go the normal route, and have two panes of laminated glass, in separate frames?

laminated both sides. 6.8mm/16mm/6.8mm.

That implies that the individual glass used to make up the laminated panes is just 3.4mm thick? Is that correct? So it would be 3.4mm+PVB+3.4mm - 16mm air gap - 3.4mm+PVB+3.4mm? Or am I misunderstanding something? If I got that right, you wont' get much isolation from that. It's very thin glass over a very thin air gap. The MSM resonant frequency will be rather high, so there won't be much isolation at all in the low end.

(split into 2 panels, 1 opening)

OK, I understand that you don't want a lot of isolation, so I suppose that's the reason why you want to have opening windows?

I do understand the isolation problem with windows but prepared to make a compromise to have some natural light.

There is no "isolation problem" from having windows, if they are designed and built correctly. I have designed quite a few studios with windows in them, and none of them have isolation problems. The only time that you would have an isolation problem with windows, is if you made them "openable": that's a recipe for disaster. But with normal fully-sealed fixed-pane windows, there should not be any problem. (assuming that each leaf has enough mass, is correctly sealed, and the air gap between them is large enough).

making a decision about an external door, looking to buy a complete finished doorset with locks pre-installed,

Your doors work as a set, not independently: They are a tuned system. The external door and its companion internal door, together, provide the isolation. You cannot judge the total isolation by looking at just one of the by itself. You need to take into account the surface density of each door, and the depth of the gap between them, plus the damping material around the edge of the gap.

In any event, neither of your options seems to be much use for a studio door. Having one door with a double-glazed unit implies that you'd end up with a three-leaf system, with all the negatives aspects for isolation associated with triple-leaves.

It would be far better (and cheaper!) to just build both doors yourself. You can build them up by starting with a solid door blank, then add a couple of layers of thick MDF, OSB or plywood to get the mass that you need. Add suitable heavy-duty hinges, add suitable seals around the door perimeter (at least two full seals), add the automatic door closer, and you are done.

the glass door would give more light, acceptable seals but big reflective surface to address,

That's not really an issue: A thick wood door would have pretty much the same reflection problems as a glass door.

Builder will be putting down a concrete base with waterproof layer

That's it! Then you are done! No more flooring required. A concrete slab on grade is the best possible acoustic floor you could ask for.

If you don't like the look of bare concrete, or wanted a warmer floor, then just lay laminate flooring directly on that, over a suitable underlay, of course. That's also a great floor, acoustically.

(not planning floating floor).

It would help if you could provide a detailed plan of what you have in mind, hopefully in SketchUp. It's not clear from the description, so either I'm misunderstanding what your plans are, or you are misunderstanding how to isolate a studio.




- Stuart -

[Pepeluis]

hi Stuart,
thank you very much for your quick reply.
You are right I need to give clearer details of my idea, my budget is definitely more than £10-12 as you rightly point out!
I will do some sketches and outline as much detail as possible and post again asap.
thanks again
Jose