John's shed

Hello, I've been lurking here for several months. I have a shed... Shape and dims as per jpegs. Construction: walls - 102.5mm brick, 50mm ful fill cavity, 100mm medium density concrete block floor - 150mm concrete slab on 75mm rigid insulation roof - concrete interlocking tiles, timber battens, felt sarking, timber rafters (it's a "couple" roof, although there are timber ties between 3 pairs of rafters), 75mm insulation between rafters, 15mm Soundblock plasterboard. roof continuously vented at eaves. door - solid core salvaged fire door, with intumescent seal. how loud: usually, not very. i prefer to monitor/mix at lower volumes, i'm quite comfortable monitoring on headphones, and most of what i record is DI'd, or "virtual". however, i also have a full drumkit (which is where the trouble really starts). I would also like to be able to rehearse/jam with 4 or 5 other musicians (i know it's a small space, but i'm used to worse) - drums, bass, guitar, vox, keys - which is why, despite having changed my mind several times every day for the last 6 months (a separate booth! with a little window and everything!) i think my most sensible layout is a single room (that, and i'd rather live with opening the door as necessary than designing/detailing/paying for hvac). although my main aim is to prevent sound getting out rather than in (external noisefloor in shed, negligible, drumkit being bashed, outside shed, oops) i am less concerned with annoying neighbours (one side, triple glazing, other side, cemetery) than attracting attention to the highly thievable goodies in my shed/feeling self-conscious about what i'm doing in here. such free time as i have dictates late night sessions, by which time the neighbourhood is mostly deathly quiet, and a pin drop sounds like a battering ram on a garage door... requirements/thoughts/questions - most urgent highlighted in bold: 1)space is at a premium. i have LOADS of "stuff" (big, old electro-mechanical/analogue stuff). isolation must be achieved with the minimum possible construction thickness. 2)i can see the attraction/versatility of john's back-to-front wall. what sort of insulation is used on the rear face, and how is it attached? 3)VERY IMPORTANT! (maybe). At present, there are no internal finishes. the soundblock ceiling is uncaulked, unskimmed. the concrete block walls are completely raw. despite pressure from mrs to "just get the ceiling plastered!" i'm holding back because i'm not sure it's the right thing to do. (i)i notice in most of the studio build threads nobody seems to plaster their walls/ceilings - what is the reason for this? (ii)what should i do with my existing walls/ceiling? is their any mileage to be gained from plastering them/ensuring maximum possible air-tightness of existing building fabric/adding another dense, well-sealed inner door ("etc"... :shock: )? should i leave them as they are and concentrate on internals? is the existing ceiling a waste of space altogether (in which case plastering it would be a complete waste of time and money)? (iii)don't even get me started on "so how many leaves does that make?". it makes my head hurt. :ahh: 4)I like the look of RISC/channel construction for the ceiling as a space-saver. I wondered how effective it would be for the walls too? 5)Yes, I have bought The Book... Budget: I really can't say, but it's tight! I just need to get it done, be able to make "some noise" without being inhibited about it, and listen to aforementioned noises. Sarm West v2 will have to wait for now! Thanks in advance, let battle commence! John

I'm going to talk out loud for a moment. Why do some rooms get built to a near completion stage and THEN questions are asked? Most of what I have gathered suggests that leakage is a concern. If your windows or doors leak you have to fix that. Caulk is sold by the case per room! If you have space or cracks or potential leaks, you have to correct these. You mentioned an approx. 6 inch thick concrete slab on approx. 3 inches of rigid insulation? Where the heck did that come from? And what is below the rigid insulation? I 'm a bit thick headed and might not get "it" all at first glance, so if I ask for a real picture or 12 it's only because it is difficult to visualize. And just to show that I am really paying attention:

2)i can see the attraction/versatility of john's back-to-front wall. what sort of insulation is used on the rear face, and how is it attached?

Inside out wall is what it is referred to as. The insulation is attached into the stud cavities that face >into< the room. The elegance of these walls are that they allow the builder to apply more mass and then to have the qualities of absorption directly on the room side when complete. In a room where space is at a premium the use of inside out wall construction will benefit the user in this area as well. After covering the insulation with a flame retardant breathable material typically a slat type finish is applied. At least that is what I got out of it :)

Hello, and thanks for the reply.

xSpace wrote:

I'm going to talk out loud for a moment. Why do some rooms get built to a near completion stage and THEN questions are asked?

I wouldn't describe this as near completion. What I have is an external shell. Its dimensions and shape are dictated by the site, UK planning guidelines and Building Regulations. Its construction is bog-standard low-end domestic construction typical of the UK, using low-cost - and dense! - materials.

xSpace wrote:

You mentioned an approx. 6 inch thick concrete slab on approx. 3 inches of rigid insulation? Where the heck did that come from? And what is below the rigid insulation?

I'm not sure what you mean by "where the heck did that come from?". The floor construction is 150mm concrete/75mm insulation/1200 Visqueen DPM/50mm sand blinding/150mm compacted hardcore/The Earth. The insulation itself is Jabfloor 70 manufactured by Vencel Resil.

xSpace wrote:

Most of what I have gathered suggests that leakage is a concern. If your windows or doors leak you have to fix that. Caulk is sold by the case per room! If you have space or cracks or potential leaks, you have to correct these.

I have no windows. The door is well-fitted and sealed, although could doubtless be improved, and I do plan to add a similar inner door. Incidentally, closing the door is like turning the outside world off! It just doesn't seem to work the other way round... I know about caulk/leaks etc, but what I am asking is whether or not such attention to the outer shell would be in pursuit of diminishing returns, and better directed at a meticulously detailed and constructed inner shell. Is there any point crawling around the building with a caulk gun to seal every inch of (e.g.) raw concrete blockwork when I could just plaster it? Is there any point plastering it if I'm going to construct independent inner walls and ceiling? I am particularly concerned about the ceiling. I have to be able to move in sooner rather than later as I have to move out of my current space. The existing ceiling works perfectly well as an ordinary ceiling. My wife is convinced it would be "finished" if I would only plaster it. I am not. I do not want to pay to have the ceiling plastered if it then transpires that my best option from a sound isolation/depth of construction point of view is to hang a ceiling from isolating clips on channels fixed to the rafters, now buried under 15mm of soundblock and a fresh coat of plaster... The outer shell is what it is, and that's that. All I can physically change (i.e.remove and replace) is the ceiling.

xSpace wrote:

Inside out wall is what it is referred to as. The insulation is attached into the stud cavities that face >into< the room. The elegance of these walls are that they allow the builder to apply more mass and then to have the qualities of absorption directly on the room side when complete. In a room where space is at a premium the use of inside out wall construction will benefit the user in this area as well. After covering the insulation with a flame retardant breathable material typically a slat type finish is applied.

I am aware of these points. However, John's wall section also shows 50mm insulation fixed to the 2 outer layers of plasterboard. My question was "what sort of insulation is used on the rear face, and how is it attached?". :) John

Hai there John, and welcome to the forum. I'd suggest taking this to the "design" part first where we can discuss the best plan for you brick-wall shed. As I understand it's only the exterior wall etc that are present? So you can build from scratch.. that's good. Now, first let's talk about what you want (in the DESIGN forum) so we can make a sketch. THEN, when your plan seems to cover what you want, we can take the design to this (construction) part of the forum to discuss HOW it's done. So, design first. Post a floorplan with dimensions. First try to come up with a design yourself (after reading all the goods on this forum). Good luck John!

Okay. It had occurred to me. My first thoughts are that it's one relatively small room, which will be required to house a dozen relatively large vintage keyboards and a drumkit (at least), and that design options are somewhat limited as a result... :oops: I was unsure whether to start by isolating the room as well as possible, and then move onto layout and treatments, or vice versa - it's not the first time it has seemed to me that the design and the construction are inextricably linked and therefore rather difficult to consider separately, but I shall do as you suggest! :) *edit* Does anyone have sketchup models of drumkits/generic behemoth electric pianos etc I could use?

Hi John, and another welcome to the forum! Here's a good place to start for your sketchup models. :wink: http://sketchup.google.com/3dwarehouse/ ... rch&styp=c Regards, Lou. 8)

that's great! thanks Lou. :D [curses self for not using google skills to find models for software owned by google...]

john h-m wrote:

Hello, and thanks for the reply. I am asking is whether or not such attention to the outer shell would be in pursuit of diminishing returns, and better directed at a meticulously detailed and constructed inner shell.

I would treat the outside with as much detail as the inside. If the exterior of this brick is porous then it can suck in moisture/water if it stays wet for any length of time. Any cracks or voids on the inside of the exterior wall joints I personally would fill.

I am particularly concerned about the ceiling. I have to be able to move in sooner rather than later as I have to move out of my current space. The existing ceiling works perfectly well as an ordinary ceiling. My wife is convinced it would be "finished" if I would only plaster it. I am not.

I wouldn't either. Make certain that all cracks are as closed as possible. You may find that you will be treating the overhead anyway, you may not. I'm thinking that "plaster" would increase the reflectiveness of this area.

I am aware of these points. However, John's wall section also shows 50mm insulation fixed to the 2 outer layers of plasterboard. My question was "what sort of insulation is used on the rear face, and how is it attached?". :)

Your right, I looked over several pages and it never did say what it was. Only thing I would think is that if it is going to be on the exterior of a building then it is going to be subject to the elements. I can't see where it is required in a building to be this thick. I can understand having a thermal barrier mind you, just not 2 inches thick :)

xSpace wrote:

I would treat the outside with as much detail as the inside. If the exterior of this brick is porous then it can suck in moisture/water if it stays wet for any length of time. Any cracks or voids on the inside of the exterior wall joints I personally would fill.

I'll be more specific (I think I may have inadvertently confused you :oops: ). I am not concerned about the weathertightness of the outer shell. It's as immune to the elements as any modern house with cavity masonry wall construction, because that's essentially what it is, albeit rather small. :) I am asking about the merits of spending time on the internal faces (at present completed only to a "builder's finish") of the external shell.

xSpace wrote:

Make certain that all cracks are as closed as possible. You may find that you will be treating the overhead anyway, you may not. I'm thinking that "plaster" would increase the reflectiveness of this area.

Again I am talking about the internal faces of the external shell, rather than what I shall be constructing within it (the internal faces of the internal shell). The existing plasterboard ceiling, if retained, would not form an interior surface of room-within-a-room. That being the case, do I leave it as it is, and get on with building my room-within-a-room, or...what? It's the ceiling that's really bugging me! Mrs wants it plastered. I don't even know if it should be there in the first place! :?

xSpace wrote:

if it is going to be on the exterior of a building then it is going to be subject to the elements. I can't see where it is required in a building to be this thick. I can understand having a thermal barrier mind you, just not 2 inches thick :)

What John is showing, is a studio wall construction within an existing building envelope. His back-to-front wall is not subject to the elements - the existing building (or "external shell") provides protection from the elements, the studio walls built within it handle isolation and acoustic treatment.

We are just on different pages. I'm going to pull out of this because I think I am generating to much confusion. Even if it is mine :?

well, it's 17 days now, and i'm under horrendous pressure, so in the absence of any actual advice i'm just going to slap another layer of soundblock over the existing ceiling, with green glue, plaster the lot, and bollocks to it, que sera sera.