My home studio project: Electric Landlady

I have described my studio project elsewhere (viewtopic.php?f=2&t=12330 and viewtopic.php?f=2&t=12326) but in the spirit of absolute clarity and consistency I thought I'd restate it here before asking new questions. I'm in Bristol (UK) and my house is a 1930s brick-built (280mm brick cavity walls: inner and outer layers of brick with foam insulation in between) bungalow that looks like drawing number one. I'm planning to build a studio which will comprise of a live room, which will be used to record and rehearse my rock bands (with live acoustic drums and guitar and bass amps, so pretty loud) and a control room which will be used for tracking and mixing, but realistically about 50% of the time used for composition, programming and teaching preparation (I'm a university lecturer in Creative Music Technology.) The constraints are: - isolation from the nearest neighbour (2m away but no windows whatsoever on that side of my house) - isolation from the street opposite; on the ground floor are shops only (so not really a problem) but there are flat on the 1st floor. It's also a moderately busy street so there is a fair amount of noise (which I don't mind, it plays in my favour if a moderate amount of noise leaks out from my studio.) - isolation from the bedroom and living room in the house; they are both some way away on the left side of the house, with the bedroom upstairs. I haven't started any work on it yet (still in the planning stages) but will start the build pretty soon (in a matter of weeks.) The live room is a concrete floor already. I have removed the existing floor from the control room; it's now to the bare foundations (concrete.) I have figured out a layout which is drawing 2. In this scenario, I'm using the outer wall as one-leaf of a two-leaf mass-spring-mass system. Difficult to see in the drawing but I'm assuming a 25mm gap, then a 100mm frame with two layers of plasterboard with green glue. In the lower room, I will build the control room, and to its left a WC and small entrance lobby to the control room (indicated in drawing 2) This should give me inner dimensions for the control room of: 2.6m x 4.065m x 4.73m which translates to the ratios: 1: 1.56:1.82 which I understand to be reasonably ok (judging by what I understand from Eric Desart's excellent "Acceptable Room Ratios" article.) I could nudge a little here or there but I'd rather not lose much width, and the length is near maximum because of the need for the WC. I'm planning to have air ducts for ventilation in the loft space above both the CR and the LR. There is a window currently in the CR but I will block it (I don't care losing the use of the window, but would rather keep it for aesthetics on the outside.) The LR has a double-door which I will retain for access. It also has a single door going outside. I'm planning to have two sets of doors for each, plus a set of double doors separating the LR and CR. Now for the new questions: Question1: I had my builder visit today and we need to start work on the studio shortly (to make a long story short: because much work needs to happen in other parts of the house, and I need the studio as temporary space.) We talked about the floor that needs building in the CR. He raised two concerns: - there are central heating system pipes in the LR that would be very difficult to redirect - bringing concrete inside the house would be difficult because of the access. So: 1) would the following scenario be any good: over the existing concrete (15inches away from intended floor): sand, then Kingspan Celotex, then IsoRubber HP6, then screed, then flooring? This scenario has the advantage that the heating system pipes can just be buried in the sand, and the respective heights of sand, Celotex and screed can be varied to suit. 2) Otherwise: given that my inner room will be (I anticipate) a single frame with two layers of plasterboard, plus the ceiling it will support, how much re-inforcing will the concrete need? And what thicknesses of sand, concrete and screed will I need, considering that the bottom is already concrete? Question2: The LR will be built into a newer extension to the house. It has a pitched (on both sides) roof that is about 4 feet high at its highest. Right now there is a loft ladder that gives me access to it for storage. Is there a way to retain this space as storage (not every day storage, but equipment cases and boxes, spare parts, that kind of stuff) while retaining sound isolation? Many thanks in advance. All advice very much welcome! Question3: I'm thinking of naming the studio "Electric Landlady" after the test pressing of Jimi's "Electric Ladyland". What does everyone think of the name? A tip of the hat or just a little too much? - martin

I dont know about question 1 since you didnt provide much graphic details about the issue and its hard to create a solution just by your short description. About reinforcing the concrete: forget it !! Concrete by itself its a big isolator. 2 layers of 5/8 plasterfoard against a 150mm concrete wall would give you a STC of 72. So you get the picture. About the ceiling. No pictures. no answer. I can't just guess the exact situation. But I tell you this: Just start with the important stuff first. then worry about the storage room. In the worst case, you'd loose it. no big deal.

Hi jbassino, I'm sorry if you feel that I didn't give enough information. I tried to be as thorough as possible without it turning into a novel. With respect to the concrete floor, I now include two diagrams that explain the options. Option 1 (floor_concrete_option.jpg): Based on what is proposed in Rod Gervais' book. 4 inches of sand, then concrete (which doesn't touch the wall), then screed. Not very practical because access difficult to bring concrete in, plus there are some heating system pipes that would be difficult to re-route. Option 2 (floor_celotex_option.jpg): The foundation is already concrete over earth, and according to Gervais: "[...]earth is a fairly good damping material, and generally you can obtain the isolation you require by simply constructing your space above that existing slab." So option 2 would be sand (say 8 inches), over which a layer of Kingspan Celotex (say 6 inches), over which 2 inches of screed. From what I understand that would have the added advantages of offering more (heat) insulation and be considerably easier to bring in. --------------- About the reinforcing of the concrete: I think you misunderstood the question. I wasn't talking about reinforcing the walls, I was talking about reinforcing the concrete. Quoting from Gervais: "It is very possible that the slab could crack and settle along the edge, causing problems with room fi nishes down the road." (Referring to a single, non-reinforced concrete slab.) So my question was asking whether in option 1 I would need reinforcing 10 inches of concrete if all it will support is a single-frame wall with two layers of plasterboard, and the ceiling attached to it. ------------------ About the ceiling: My question was whether there is a "known" solution to a hatch in the ceiling, much in the same way that "window plugs" are a solution for retaining occasional access to a window. I don't have more details because I assume that this will determine how I make the ceiling. If there is no known solution then I'm happy to abandon the hatch idea, but I'm guessing there must be cases where people still needed access to upper ceilings for piping, ducts, electrics, etc. I'm happy to provide a picture of the existing ceiling and hatch, but it's just that: a plasterboard ceiling attached to ceiling joists, with an opening in which I have installed a loft ladder hatch. Many thanks, - martin

viewtopic.php?t=8173 It is usually a waste of a lot of money to isolate a concrete foundation floor. Your walls and ceiling will be a weaker link for sound to escape.

Thanks petrovinsky. That's more or less what I thought, which is why I came up with option 2. I still need to raise the floor by about 400mm to level with the existing concrete in the LR. Would the option 2 that I proposed be any good? - martin

Martin - the simplest way to float a new slab is to use this method. Basically - you lay down a plastic vapour barrier. On top of that you lay 1" (25mm) rigid fiberglass/rockwool. Then a layer of homosote or plywood or MDF followed by another layer of 1" (25mm) rigid fiberglass/rockwool also extending it up the wall. You then add another plastic barrier, add your reinforcing mesh and supports. Then you pour the slab on top of it all. The weight of the concrete will compress the fiberglass and the whole slab is then isolated from the rest of the building. You then build your internal walls directly onto the new slab. BTW - I love Electric Landlady :) :)

yeah, haha the name is cool. As a huge JH fan I can appreciate the fun name :)

Thanks for the replies. John, that is a very elegant and simple solution. Thank you very much for that. What thickness would you recommend for the concrete slab? Also, I have a concrete foundation already, and the finished floor needs to be about 300mm above the concrete foundation; can I put sand in between the concrete foundation and the rockwool/homasote/rockwool layer? Once again many, many thanks for the excellent answer. Two votes in favour and none against "Electric Landlady." I think it's a keeper! :) - martin

yes - you could use sand to bring it up to height so you only need a 100mm (4") slab. That is how all the floating slabs at Record Plant and studios of that ilk were done.

Brilliant! That is a great relief. Many thanks John! - martin