East Sussex - Double Garage draft design
Posted: Thu Mar 14, 2019 4:23 am
Build thread here:http://www.johnlsayers.com/phpBB2/viewt ... =2&t=22291
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Hello & howdo’?
This is my first post to John Sayer’s Recording Studio Design Forum and I would like to begin with a word of praise for John, the administrators and moderators for the excellent resource that they have built. It truly is “A World Of Experience” as the 'strap - line’ says and all the more remarkable for being independent, free to use and based on trust; there are precious few things in the world (never mind on the internet) that can claim that!
My name is John and I’m developing a design to convert a double garage into a music practise room which can also be used to track instruments including drums and electric guitars.
The building is in East Sussex, in the South East of England which has a temperate climate, situated in a residential area, on a hill, amongst woodland and is detached from our house. The garage is at the edge of a levelled area cut into the side of the hill, so the South-Eastern aspect of the building is built into the earth to a height of 131cm (4’4”).
It sits on a 4” (10cm) concrete base and internal dimensions are 4.85m x 4.98m (15’11” x 16’04”) - almost square! There is a half-hipped roof which is 4.46m (14’7”) at the highest internal point. The walls consist of a single tier of brick and are buttressed on 3 sides with breeze block columns, roughly at the centre point of each wall. There is a structural beam which runs from from the North-West wall to the South-East wall at a height of 2.24 M (7’4”). The North-West wall has an outward opening door and window and the South-West aspect has two large openings for the garage doors. I have attempted to model the room as accurately as possible using Sketchup.
Although I have learned a great deal of very useful information from Rod Gervais and F. Alton Everest’s excellent books (as well as this forum) I won’t pretend that I don’t have a great deal more to learn and I’m fully prepared to do this. Here is a brief outline of what I think I know about achieving my aim - I would be very grateful for any comments, criticism or suggestions if any of you have the (precious) time and inclination.
I have measured the ambient sound level in the area surrounding the garage at 35dB on a windless day and up to 68dB when the wind shakes nearby trees. Passing traffic sometimes elevates the level to 70dB and the occasional light aircraft passing nearby will give a reading of 55dB.
The loudest instruments I am going to record are drums (I tend to DI bass when recording) which I have measured peaking at up to 116 dB. Local noise regulations are non-specific when it comes to defining an actual level at which sound becomes a nuisance, but as we have neighbours at both sides (6m and 12 metres) I am aiming for a sound transmission reduction of 55dB or greater and while this is ambitious, the handy transmission loss calculator suggests that it’s possible, so I’m optimistic that it can be achieved. I have a budget of £15,000 - £18,000 and intend to undertake as much of the work as I practically can (although I will not attempt any electrical work, fitting the HVAC system or acoustic windows or doors - I would rather pay experienced professionals to do those parts of the job).
I plan to build a single room within a room consisting of two leaves (where possible*). The outer leaf will consist of the existing single tier, solid brick wall which will be sealed, up to a height of 221cm, then a combination of 18mm OSB and 2x 19mm gypsum board to meet a ceiling of similar construction, supported by the existing and some additional ceiling chords (I have consulted a structural engineer who tells me that with the correct reinforcement to the chords and lowest beam, this is both possible and safe).
The South-West aspect of the building has two large “up and over” garage doors which will need immobilising, sealing and damping with mass loaded vinyl (or similar) before a 18mm OSB and 2x 19mm gypsum board wall (supported by 2x4 stud) is built in each gap. I realise that this in effect creates a 3 leaf system*, but I don’t see a way around this other than simply bricking up the gap which is unfortunately not an option in this case.
The inner leaf will be 2x19mm gypsum board with green ’glue’ in between, attached to a stud frame anchored to the concrete floor with an air gap of at least 30 centimetres between the leaves, which will be loosely filled with rock wool. The inner leaf frame will support a ceiling of similar construction at a height of 233cm (7’7”) which will be lowered in the middle of the room in order to avoid the structural beam which runs from the centre of the the North-Eastern Wall to the South-Western Wall. The existing window will be replaced on the outer leaf with a fixed one, glazed with 21mm laminated glass and one on the inner leaf using 12mm glass, conforming to the design in chapter 5 of the second edition of Rod Gervais’s book. The existing door will be removed and two, triple sealed doors (as similar to Rod’s “super door” as possible) will be installed with closers. I would ideally like to add laminated glass windows to the doors (I have spent far too many hours working in dark rooms)
but my calculations suggest that it would cause them to be very heavy!
I have (so far) been unable to calculate the ventilation load for this room, so I intend to talk to a professional air conditioning engineer about local humidity and other requirements for AC** (luckily, I know one locally who has installed AC in studios before). It will need fresh air for up to 5 people (75 cubic feet per minute) which will be pulled though the room by an inline fan, although more often there will be only one or two people occupying the room. I will build 4 baffles, one for each time the ventilation system penetrates a leaf and I will need an appropriately sized mini - split system for temperature and humidity control **.
I know that the limited space will make acoustic treatment more difficult - I intend to put bass traps in the two windowless corners and attempt to create a variable acoustic using dual purpose absorber / reflectors which can be moved along wall mounted rails or used as free-standing units on the floor, depending on the desired environment.
I’m sure there is much I have overlooked in this and other areas, but before I go into detail I’m curious to know if this idea is at all viable or could, at least, form the basis of a better design.
I would also like to ask a couple of questions. The concrete floor is not exactly level - it has been poured in two halves and at the North-East end of the room, one is roughly 1cm (less than half an inch) higher than the other. Is this difference tolerable or should I level the floor? I would also like to know what the most effective material for sealing the brick wall: damp seal, masonry paint or is there a better compound?
Thank you for reading my ramble and best wishes. John.
===============================================================================================
Hello & howdo’?
This is my first post to John Sayer’s Recording Studio Design Forum and I would like to begin with a word of praise for John, the administrators and moderators for the excellent resource that they have built. It truly is “A World Of Experience” as the 'strap - line’ says and all the more remarkable for being independent, free to use and based on trust; there are precious few things in the world (never mind on the internet) that can claim that!
My name is John and I’m developing a design to convert a double garage into a music practise room which can also be used to track instruments including drums and electric guitars.
The building is in East Sussex, in the South East of England which has a temperate climate, situated in a residential area, on a hill, amongst woodland and is detached from our house. The garage is at the edge of a levelled area cut into the side of the hill, so the South-Eastern aspect of the building is built into the earth to a height of 131cm (4’4”).
It sits on a 4” (10cm) concrete base and internal dimensions are 4.85m x 4.98m (15’11” x 16’04”) - almost square! There is a half-hipped roof which is 4.46m (14’7”) at the highest internal point. The walls consist of a single tier of brick and are buttressed on 3 sides with breeze block columns, roughly at the centre point of each wall. There is a structural beam which runs from from the North-West wall to the South-East wall at a height of 2.24 M (7’4”). The North-West wall has an outward opening door and window and the South-West aspect has two large openings for the garage doors. I have attempted to model the room as accurately as possible using Sketchup.
Although I have learned a great deal of very useful information from Rod Gervais and F. Alton Everest’s excellent books (as well as this forum) I won’t pretend that I don’t have a great deal more to learn and I’m fully prepared to do this. Here is a brief outline of what I think I know about achieving my aim - I would be very grateful for any comments, criticism or suggestions if any of you have the (precious) time and inclination.
I have measured the ambient sound level in the area surrounding the garage at 35dB on a windless day and up to 68dB when the wind shakes nearby trees. Passing traffic sometimes elevates the level to 70dB and the occasional light aircraft passing nearby will give a reading of 55dB.
The loudest instruments I am going to record are drums (I tend to DI bass when recording) which I have measured peaking at up to 116 dB. Local noise regulations are non-specific when it comes to defining an actual level at which sound becomes a nuisance, but as we have neighbours at both sides (6m and 12 metres) I am aiming for a sound transmission reduction of 55dB or greater and while this is ambitious, the handy transmission loss calculator suggests that it’s possible, so I’m optimistic that it can be achieved. I have a budget of £15,000 - £18,000 and intend to undertake as much of the work as I practically can (although I will not attempt any electrical work, fitting the HVAC system or acoustic windows or doors - I would rather pay experienced professionals to do those parts of the job).
I plan to build a single room within a room consisting of two leaves (where possible*). The outer leaf will consist of the existing single tier, solid brick wall which will be sealed, up to a height of 221cm, then a combination of 18mm OSB and 2x 19mm gypsum board to meet a ceiling of similar construction, supported by the existing and some additional ceiling chords (I have consulted a structural engineer who tells me that with the correct reinforcement to the chords and lowest beam, this is both possible and safe).
The South-West aspect of the building has two large “up and over” garage doors which will need immobilising, sealing and damping with mass loaded vinyl (or similar) before a 18mm OSB and 2x 19mm gypsum board wall (supported by 2x4 stud) is built in each gap. I realise that this in effect creates a 3 leaf system*, but I don’t see a way around this other than simply bricking up the gap which is unfortunately not an option in this case.
The inner leaf will be 2x19mm gypsum board with green ’glue’ in between, attached to a stud frame anchored to the concrete floor with an air gap of at least 30 centimetres between the leaves, which will be loosely filled with rock wool. The inner leaf frame will support a ceiling of similar construction at a height of 233cm (7’7”) which will be lowered in the middle of the room in order to avoid the structural beam which runs from the centre of the the North-Eastern Wall to the South-Western Wall. The existing window will be replaced on the outer leaf with a fixed one, glazed with 21mm laminated glass and one on the inner leaf using 12mm glass, conforming to the design in chapter 5 of the second edition of Rod Gervais’s book. The existing door will be removed and two, triple sealed doors (as similar to Rod’s “super door” as possible) will be installed with closers. I would ideally like to add laminated glass windows to the doors (I have spent far too many hours working in dark rooms)
but my calculations suggest that it would cause them to be very heavy!
I have (so far) been unable to calculate the ventilation load for this room, so I intend to talk to a professional air conditioning engineer about local humidity and other requirements for AC** (luckily, I know one locally who has installed AC in studios before). It will need fresh air for up to 5 people (75 cubic feet per minute) which will be pulled though the room by an inline fan, although more often there will be only one or two people occupying the room. I will build 4 baffles, one for each time the ventilation system penetrates a leaf and I will need an appropriately sized mini - split system for temperature and humidity control **.
I know that the limited space will make acoustic treatment more difficult - I intend to put bass traps in the two windowless corners and attempt to create a variable acoustic using dual purpose absorber / reflectors which can be moved along wall mounted rails or used as free-standing units on the floor, depending on the desired environment.
I’m sure there is much I have overlooked in this and other areas, but before I go into detail I’m curious to know if this idea is at all viable or could, at least, form the basis of a better design.
I would also like to ask a couple of questions. The concrete floor is not exactly level - it has been poured in two halves and at the North-East end of the room, one is roughly 1cm (less than half an inch) higher than the other. Is this difference tolerable or should I level the floor? I would also like to know what the most effective material for sealing the brick wall: damp seal, masonry paint or is there a better compound?
Thank you for reading my ramble and best wishes. John.