House Extension with a Dedicated Home Cinema Room

Triggaaar

Distinguished Member
The very first film I watched in my room was before AC was fitted. Admittedly it was August and the internal temp started at 22 degrees.

4 of us were in the room, really excited at the first ever viewing in my purpose built cinema.

We got 45 minutes in before giving up, the temp had risen to 27 degrees and felt like 40! It is in effect the same as Sauna. Loads of body heat and nowhere for it to escape to.

I didn’t watch another film until AC was fitted.
I remember reading this from you before, but that didn't compare to using simple ventilation, and your build may be a little different, as it's a stand alone building.
 

mb3195

Distinguished Member
I remember reading this from you before, but that didn't compare to using simple ventilation, and your build may be a little different, as it's a stand alone building.
you’re right, mine is completely sealed with no ventilation.

it might be different at yours, but nothing worse than watching a film being all hot and sticky.

AC gives you comfortable temperature all year round.
 
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Apollo

Well-known Member
This discussion is getting a bit circular now and I believe @Harkon321 has already made his own mind up on the benefits and necessity of climate control. He is welcome to ask any questions of those of us with a history of dedicated rooms so equipped.

I’ll leave it to him to argue the requirement to make the extra expenditure with the domestic authorities :)
 

Triggaaar

Distinguished Member
you’re right, mine is completely sealed with no ventilation.

it might be different at yours, but nothing worse than watching a film being all hot and sticky.

AC gives you comfortable temperature all year round.
Oh undoubtedly it's best if you have AC. The question is whether you have to have it. Maybe in 9 months I'll be back here, retrofitting and saying you absolutely have to have it, but I'm not yet sure that's the case. I wouldn't be at all surprised if there are a few days a year when it's just too hot for me to watch a film, but I'm hopeful that on the more ordinary hot days, basic ventilation will be enough.
 

Harkon321

Well-known Member
Thanks for the opinions and input everyone. It is welcomed and gives me plenty to think about.

Roof is now insulated and boarded and the facia started. Not an exciting photo I grant you but ...

B95BCF82-9222-4A51-B0C4-FDDBBF47CFCA.jpeg
 

adam-burnley

Distinguished Member
FWIW I decided not to put AC in my room, mainly because there was no decent position for the external box. All kit is in the room, and other than the very hottest days (maybe 2 this year), it's never been an issue.

Granted its always cold up north though.

If you can accommodate and afford it then get it. It's better to have AC than not, although I'd prefer it throughout the house, not just the cinema room.
 

IWC Dopplel

Distinguished Member
I think insulated (soundproof) modest size rooms with low ceilings and plenty of kit will be a challenge in the summer
 

Harkon321

Well-known Member
I have to say, I'm quite jealous of the speed of your build :)
Considering the issues with the roof last week I've been really impressed with the builders, they've worked really hard. Often just the builder and his dad as the labourer has hurt his back.

Only just came across this thread. Just want to know how far along are you with the inside. Have you decided on your sound proofing??
Still bare concrete blocks on the inside. No final decisions yet, but think I'm going for the following:

Existing outside wall of the house (300mm brick/cavity/block - 100mm stud work and 100mm rockwool, decoupled from the wall. OSB Board, then Green Glue, then heavy plasterboard. LCR in wall speakers also in this wall with double skin 'backer boxes'

New 100mm block work - dividing cinema from kitchen - Same as above but 75mm decoupled stud work (We've got loads of this left from the pitched roof that didn't happen so may as well use it!

Remaining two new exterior walls - These are already 300mm brick/cavity/block. They will be faced with double layer of plasterboard and green glue in between.

Ceiling - As above

Window - Intend to build a 100mm frame and fit plasterboard/greenglue both sides, fill with rockwool and fit in the gap. Need to include a fire exit door of some sort.
 

makaveli187

Active Member
Considering the issues with the roof last week I've been really impressed with the builders, they've worked really hard. Often just the builder and his dad as the labourer has hurt his back.



Still bare concrete blocks on the inside. No final decisions yet, but think I'm going for the following:

Existing outside wall of the house (300mm brick/cavity/block - 100mm stud work and 100mm rockwool, decoupled from the wall. OSB Board, then Green Glue, then heavy plasterboard. LCR in wall speakers also in this wall with double skin 'backer boxes'

New 100mm block work - dividing cinema from kitchen - Same as above but 75mm decoupled stud work (We've got loads of this left from the pitched roof that didn't happen so may as well use it!

Remaining two new exterior walls - These are already 300mm brick/cavity/block. They will be faced with double layer of plasterboard and green glue in between.

Ceiling - As above

Window - Intend to build a 100mm frame and fit plasterboard/greenglue both sides, fill with rockwool and fit in the gap. Need to include a fire exit door of some sort.
Is the cavity of the external wall insulated.

you could do away with the 100mm stud wall and use genie clip system to save space and decouples the wall with less space used.
This might not suit for in wall speakers depending on the depth of speakers.

Instead of using 18mm osb as you base layer use 15mm sound bloc will work out cheaper per board and better for sound.
ontop of this use a product called tec sound Instead of green glue. this product decouples and adds mass then another 15mm soundbloc.
This is the system I have used and I am getting roughly 65 Db reduction in sound from inside to outside.
 

IWC Dopplel

Distinguished Member
My room must be the exception then
I guess part of it will be how much equipment heat generation is going on and if the sun heat soaks external walls.
 

Harkon321

Well-known Member
@makaveli187

Thanks for your feedback, glad you’re happy with your set up. 65db is impressive.
The 100mm wall will house 95mm deep in wall speakers, meaning I can save space and get an acoustic transparent screen without losing room depth. Not sure how much depth I’d save with genie clips. I’d still need studs with insulation and they are only 2cm max off the wall. Or did you fix the genie clips straight to the block wall. I think genie clips come in to their own when you’re dealing with existing stud work in place.

Tecsound is good stuff but the data I saw suggested a 3rdlayer of PB is cheaper and as effective. Green Glue is for damping of LFE rather than mass, although I don’t doubt adding more mass has the same effect.

I need to check the density of sounbloc and OSB.OSB just makes hanging fabric panels, screen etc a lot easier.
 

Triggaaar

Distinguished Member
Instead of using 18mm osb as you base layer use 15mm sound bloc will work out cheaper per board and better for sound.
I may use 2 layers of plasterboard, but many people prefer to use osb for the base layer as it makes fixing things easier.

ontop of this use a product called tec sound Instead of green glue. this product decouples and adds mass then another 15mm soundbloc.
Isn't tec sound more expensive than green glue and plasterboard for mass?
 

makaveli187

Active Member
I may use 2 layers of plasterboard, but many people prefer to use osb for the base layer as it makes fixing things easier.

Isn't tec sound more expensive than green glue and plasterboard for mass?
Ya osb is a lot handier for fixing afterwords but Osb won’t give same benefits sound wise as a sound bloc board.

Adding a 3rd layer is not worth the return on the DB reduction achieved its minimal unless another layer of tec sound or green glue is used.

Genie clips can be mounted to block wall or stud then there’s a hat channel slipped into them.

a cheaper option is resilient bars.
When used the bars and hat channels become your mounting points for panels shelf’s screen etc.

tec sound for me cost about €90 per roll and one roll cover roughly 2 8x4 slabs.
 

makaveli187

Active Member
@makaveli187

Thanks for your feedback, glad you’re happy with your set up. 65db is impressive.
The 100mm wall will house 95mm deep in wall speakers, meaning I can save space and get an acoustic transparent screen without losing room depth. Not sure how much depth I’d save with genie clips. I’d still need studs with insulation and they are only 2cm max off the wall. Or did you fix the genie clips straight to the block wall. I think genie clips come in to their own when you’re dealing with existing stud work in place.

Tecsound is good stuff but the data I saw suggested a 3rdlayer of PB is cheaper and as effective. Green Glue is for damping of LFE rather than mass, although I don’t doubt adding more mass has the same effect.

I need to check the density of sounbloc and OSB.OSB just makes hanging fabric panels, screen etc a lot easier.
My take on it when I was researching what way to go was green glue or tec sound won’t damp or decouple the wall good enough to stop LFE from passing to walls and stoping them from coming “live” this is where the resilient bars/ genie clips come into play.

with your 100mm stud wall be carful where it is fixed to i.e Side walls ceiling joist. LFE will pass tru these fixing points and shake everything.
when fixing to floor you should put rubber strip under your base plate. This will help with transfer to floor.
 

Harkon321

Well-known Member
I didn't realise you could fix genie clips straight to the block. Depends if I want insulation or not I guess. Good idea though.

My take on it when I was researching what way to go was green glue or tec sound won’t damp or decouple the wall good enough to stop LFE from passing to walls and stoping them from coming “live” this is where the resilient bars/ genie clips come into play.
Ye on it's own it won't, I agree. I've even seen reports that say not to bother with Green Glue unless you can decouple the walls anyway. The two new outside walls are mainly decoupled other than the brick ties. That plus the mass of 2 x 100mm brick walls and insulation in between will stop most of the noise.
with your 100mm stud wall be carful where it is fixed to i.e Side walls ceiling joist. LFE will pass tru these fixing points and shake everything.
when fixing to floor you should put rubber strip under your base plate. This will help with transfer to floor.
The room sits on it's own concrete slab (we had 2 poured) so not sure whether I'll add the rubber under the studs or not. The stud will be fixed to floor and ceiling joists but using IB3 acoustic brackets to connect the two. (has a rubber mount).
 

Apollo

Well-known Member
Ya osb is a lot handier for fixing afterwords but Osb won’t give same benefits sound wise as a sound bloc board.
Sorry, I don’t believe you are quite correct on that.

Using 18mm OSB3 in place of 15mm Sounbloc is very effective as they will have a similar weight per m2. The density will be different however I believe this is a good thing in soundproofing. The overall mass of each layer will be similar.

The benefits of being able to bang screws in wherever you like to mount heavy items like screens, A/C, wall mounted speakers and additional room features like soffits is invaluable.

The independent stud wall is hard to get wrong, other methods of construction using resilient channel for example can be ruined by misplaced screws.
 

Harkon321

Well-known Member
Thinking about this a bit more. Using a Mass-Air-Mass wall to stop sound transfer is broadly based on two things - mass and the size of air gap. Increase either, and the effectiveness of stopping the lowest frequencies increases. If I just use genie clips (straight to the block), the wall would be isolated and have the same mass, but the air gap non existent. Therefore the frequencies for which it would be effective would be much higher, and Lfe would be harder to stop.
 

makaveli187

Active Member
Sorry, I don’t believe you are quite correct on that.

Using 18mm OSB3 in place of 15mm Sounbloc is very effective as they will have a similar weight per m2. The density will be different however I believe this is a good thing in soundproofing. The overall mass of each layer will be similar.

The benefits of being able to bang screws in wherever you like to mount heavy items like screens, A/C, wall mounted speakers and additional room features like soffits is invaluable.

The independent stud wall is hard to get wrong, other methods of construction using resilient channel for example can be ruined by misplaced screws.
[/QUOTE
An 8x4 sheet of sound bloc slab is 44kg.
osb at 18mm 8x4 is approx 36kg.
i was goin to go the osb route myself but changed to sound bloc due the me using the bars as you said misplaced screw and allthe work that went into the bars is gone. So I’m governed to where my bars are at least I know il avoid the studs.

it’s a big rabbit hole to dive into multiple ways of doin things and price can sky rocket.
 

makaveli187

Active Member
Thinking about this a bit more. Using a Mass-Air-Mass wall to stop sound transfer is broadly based on two things - mass and the size of air gap. Increase either, and the effectiveness of stopping the lowest frequencies increases. If I just use genie clips (straight to the block), the wall would be isolated and have the same mass, but the air gap non existent. Therefore the frequencies for which it would be effective would be much higher, and Lfe would be harder to stop.
I’m not 100% on fixing clips direct to wall.
Air gaps work best for higher frequencies but not as well for lower unless the walls are isolated.
clips and channel will give nearly 40mm.
Be careful wit the size of air gap you use as bigger isent always better.
I hav an 18mm gap between back of slab to my airtight membrane and rock wool.
I felt the more I researched and questions I asked the worse the decision making became. You should set your head on somethin and go with it.
 

Apollo

Well-known Member
An 8x4 sheet of sound bloc slab is 44kg.
osb at 18mm 8x4 is approx 36kg.
i was goin to go the osb route myself but changed to sound bloc due the me using the bars as you said misplaced screw and allthe work that went into the bars is gone. So I’m governed to where my bars are at least I know il avoid the studs.

it’s a big rabbit hole to dive into multiple ways of doin things and price can sky rocket.
Not sure where you are getting 44kg per sheet from unless we are talking about different products or my calculator is broken?

Assuming we are talking about plain (blue) Gyproc SoundBloc 15mm it is 12.6kg m2. I make that 36kg per 2400x1200 sheet. OSB3 ranges between 32-36kg for 2440x1220 boards depending which you buy.

Not much in it apart from the OSB is lower density overall but the mass is similar. There are other variants of acoustic plasterboard with higher mass or thickness but they don’t seem as readily available.
 

Harkon321

Well-known Member
Air gaps work best for higher frequencies but not as well for lower unless the walls are isolated.
clips and channel will give nearly 40mm.
Be careful wit the size of air gap you use as bigger isent always better.
I hav an 18mm gap between back of slab to my airtight membrane and rock wool.
Sorry, to clarify, I'm counting air gap as the gap between the two areas of mass (i.e. where you're rockwool is). And in that case, the bigger the air gap, the lower the frequency range the wall will work at. SO in total mine will be 120mm air gap on the front wall and 95mm air gap on the sides. That is stud with rockwool plus small gap to isolate.
 

Harkon321

Well-known Member
It was already starting to drop dark by the time I managed to get back tonight but roof is fully boarded and most of the facia and guttering is done.

Debating where to put lighting outside if anyone wants to chime in.

Thinking 3 'UpDown lights' spaced in the middle of each pillar of brick.
Was also thinking of 3 Soffit lights, one above each pane of the bifold.

Thoughts?


IMG_5524 (1).jpeg
 

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