Hi,
Long term reader and 1st time poster. Hope this is ok.
Bit of random background:
We are currently in the middle of the main structural work for a loft conversion in our 3 bed, fairly typical, limestone walled Victorian terrace.
I say main structural work, this includes roof windows, steel spans party wall to party wall, joists and a 10” steel A frame to sit alongside the existing oak A frame, span and kingpin and take over the whole roof load.
Due to the roof setup the steel comes into the rooms below to hit the wall and padstones
. The steel will be clad in fire board and stuffed with glass wool to minimise the cold bridge. In the bedrooms below it will stuffed with glass wool and clad in wood with intumescent paint to match the existing oak beam cover.
Actual Questions:
Anyway, what I am trying to get my head around, and would really appreciate some help on, is the best way to approach both insulation and sound reduction as we live on a main road and the last thing I want is a massive failure of some unusable space due to road noise or it being like a fridge.
Our current thinking was as follows (to comply with Building Regs and cut down the sound transfer we hope).
For the floor space we plan to use a min of 200mm of glass wool between the existing ceiling joists in a chicken wire basket (or sheep’s wool if we can afford it so the timber will breathe, maybe a blend) and then put new joists hanging off jiffy hangers from the steels between the party walls and A frame.
We also plan to put joist strips on the floor before adding floorboards for the finish floor to soak up some impact noise.
As far as I can tell this should cover the needs of building regs and should also give us a fighting chance at ending up with a usable and fairly quiet space.
Moderate reduction in sound coming in from outside and minimal being transferred to the floor below. Not perfect by any means but better than nothing.
For reference all roof windows are being placed on the rear of the house away from the road so the road face is all just clay tiles.
Before we go much further down this path I would love some opinions as our builder is quite ok with the idea but thinks it is overkill for a bit of noise, more than happy to build to our specs however.
Building control don’t really care about acoustics apart from minimal work to regs and seem to be mainly worried about the steel install and resulting U value of the space.
Me, well I am not sure it is enough and would rather do it once and right so we can actually use the room day to day.
Thanks,
John
Long term reader and 1st time poster. Hope this is ok.
Bit of random background:
We are currently in the middle of the main structural work for a loft conversion in our 3 bed, fairly typical, limestone walled Victorian terrace.
I say main structural work, this includes roof windows, steel spans party wall to party wall, joists and a 10” steel A frame to sit alongside the existing oak A frame, span and kingpin and take over the whole roof load.
Due to the roof setup the steel comes into the rooms below to hit the wall and padstones
. The steel will be clad in fire board and stuffed with glass wool to minimise the cold bridge. In the bedrooms below it will stuffed with glass wool and clad in wood with intumescent paint to match the existing oak beam cover.Actual Questions:
Anyway, what I am trying to get my head around, and would really appreciate some help on, is the best way to approach both insulation and sound reduction as we live on a main road and the last thing I want is a massive failure of some unusable space due to road noise or it being like a fridge.
Our current thinking was as follows (to comply with Building Regs and cut down the sound transfer we hope).
Insulate between rafters and in the dropped area under the ridge with as much PIR as we can get in (about 70mm with airgap to the breathable membrane and under ridge). Tape and seal. This goes down as close to the eaves as we can get.
Insulate over the top with another 70mm of PIR staggering the joins and tape and seal just about everywhere. May use a little less if we can get away with it.
Build in dwarf wall. Put Rockwool style batts between studs (100mm thick?) for an extra sound and thermal break.
Attach resilient bars in place of timber batons to the rafters and dwarf wall with screws through the top 70mm PIR or direct into dwarf wall studs. This should provide an air gap, acoustic break and something for the plasterboard to sit on.
Could this also be done on the party walls?
Attach 12.5mm acoustic plasterboard to the resilient bars, tape and joint then skim with the denser acoustic plaster.
For the floor space we plan to use a min of 200mm of glass wool between the existing ceiling joists in a chicken wire basket (or sheep’s wool if we can afford it so the timber will breathe, maybe a blend) and then put new joists hanging off jiffy hangers from the steels between the party walls and A frame.
We also plan to put joist strips on the floor before adding floorboards for the finish floor to soak up some impact noise.
As far as I can tell this should cover the needs of building regs and should also give us a fighting chance at ending up with a usable and fairly quiet space.
Moderate reduction in sound coming in from outside and minimal being transferred to the floor below. Not perfect by any means but better than nothing.
For reference all roof windows are being placed on the rear of the house away from the road so the road face is all just clay tiles.
Before we go much further down this path I would love some opinions as our builder is quite ok with the idea but thinks it is overkill for a bit of noise, more than happy to build to our specs however.
Building control don’t really care about acoustics apart from minimal work to regs and seem to be mainly worried about the steel install and resulting U value of the space.
Me, well I am not sure it is enough and would rather do it once and right so we can actually use the room day to day
.Thanks,
John
