Precast Garages

Hi, first of all a big THANKS to the community for this great resource. Here in Germany there are are many suppliers who sell precast garages (precast reinforced concrete construction), that are delivered complete (or more modules depending on size) and are simply put up on a strip foundation. They are relatively cheap, about 280 EUR/m². The walls are 80mm thick. Standard height is 250cm. One can buy them second hand too. Garages are the standard application for this kind of buildings, but they are used for a wide range of purposes. So I'd like to use them as...surprise...a studio (tracking & mixing, all instruments, loudest one drums, no full band!) :D Of course this is somewhat similar to the container studios, which are known in the forum. But here in Germany these objects are cheaper than "container buildings", and I think 8 cm reinforced concrete must provide better sound insulation or at least be a better foundation for a high insulation construction. At a premium one can design the objects freely. All in all, I'd see many advantages:

- fast, easy, and relatively cheap - readymade room with already good amount of sound insulation (?), ideal room dimensions and geometry, windows, doors, etc. in place - for more rooms one can use more modules, put them up very close, which results in a good room-to-room-insulation - mobility (transport is not that cheap, but worthwhile if I should relocate) - flexibility, simply add new modules - secure investment, better than investing in a rented space, one could even sell the whole thing.

But still my main questions: - How much sound insultaion will such an object provide? Will I need an additional drywall construction for "drum level"-insulation? (I WILL need heat insulation anyway) Should I go for thicker walls? Maybe anyone has some experience with such objects... Any comments and ideas are very much appreciated! Thanks & Regards!

Do you have a link to an example?

Yes: http://www.zapf-gmbh.de/garagen/garagen ... lerie.html http://www.ott-garagen.de/mehrzweckraum-beispiele.php http://www.atlas-garagen.de/wohnraummodule.htm http://www.elementbau-schlangen.de/refe ... sicht.html Thanks!

Wow! There was some cool stuff there, especially the zapf link. All of your advantages make complete sense to me and I see no reason you couldn’t make it work with a little effort. I have no first hand experience with them of course, but the obvious weak spot would be the garage door part of it. If you could order one without then problem solved. The next weakest spot will probably be the roof. As for isolation, how close are your neighbors? If they’re close, you’ll more then likely need to frame up new internal walls and ceiling with additional drywall to battle the onslaught of a drum kit. I’ve never dealt with walls like the ones of those buildings, but I haven’t personally met a one leaf system that could defeat a drum kit yet. None the less, I like this option and would consider it myself if I had the money and space to do it.

As Delusion wrote, a second wall will be required for good isolation. 80mm is good for low frequency isolation, but not higher frequencies. It will provide around 45 STC, or Rw isolation. Adding a second wall of gypsum board with insulation in between will bring the isolation up around 4 to 6 points. Andre

thanks for your interest@delusion! EDIT: and Avare Yes, there are even some cool design and placement (hillside, into the ground) options. One can order these objects without the typical garage door, some suppliers even offer sound insulation doors. The roof is made out of reinforced concrete too, and is even thicker than the walls, I think. There is also an greening option for the roof, which - according to the manufacturer - increases insulation both in terms of sound and heat. The neighbors aren't too close and there are barns and gargages between me and them. But however, I want a solution as good as possible, as I will probably relocate in some years. I have virtually no first hand practical experience in studio construction, but intuitively (dangerous in sound insulation, I know) I think adding an inner room with 2-3 layers of drywall with fiberglass (the latter I need anyway for heat insulation) could do it. The idea that concrete walls (or any wall) can block low freqs but let through hi freqs is COMPLETELY new to me. I'd like to do the inner construction in a way that I can disassemble it at the points of intersection of the outer concrete modules (I think I'm gonna get 2-3) relatively easy (without any or much destructive work) and move and relocate the modules with its inner shells as a whole. Then it should be possible to put them on the new location and start working almost instantly. With regard to money I think for me it's a more secure investment. If someone owns a house and builts his studio in it and gets into trouble (financial, noise, etc.) the investment is maybe completly gone. A garage-studio like that could be sold. Actually I wanted to use the attic of the rented house I live in but for design, contractors, material I would have to spend at least 5000 EUR (the owners would have paid another 5000 EUR), and noone could really guarantee that I get an amount of sound Insulation which I can somehow work with (let alone drum level insulation). If I ever relocate, the investment was gone anyway. If the whole idea works, one (or some STUDIO DESIGNERS) could even think of making and selling ready made modular studios. Thanks & Regards!

For the internal room, you could build John's "inside out" walls in a modular fashion and then take them apart when you move. With a little planning, you could probably even do the ceiling in modular segments and lift them into place with enough help. Seal it up really well, and I think 2 layers of 5/8" drywall should get you there. 3 layers would make everything harder to put up and disassemble considering the modular fashion you're after...but it could be done...lifting ceiling sections into place with 3 layers would be more then I would want to try. The green roof option would only add to the isolation and would be a cool addition.

How the cost of the precast compare with building walls with drywall? If it is close in cost, build a double wall. The isloation you would get would be similar to the third attachment. The second attachment shows a 190mm hollow concrete block wall with drywall attached. For comparison, and showing what double drywall does, attachmet one is of a heavy duty double drywall. Notice the low isolation at low frequencies. Andre

Thank you very much for your input guys! Update (I posted the same in another thread): Prices here in Germany start from about 200 EUR/m². There are various systems. Some come as a whole and are also poured as a whole. Some come in large parts and need to be assembled by the suppliers team. Some come as building blocks, which one can assemble by themselfs. I have insulation data for the latter, the manufacturer says 36dB. I called my acoustics consultant, he thinks the "building blocks"-system probably have better insulation data, than the other ones.