*Treatment stage* Fen Cabin Studio - Build Diary. UK

Outerleaf wall insulation finished today. Just need to staple my netting on to make sure it's secure. Then it's time to hoover and caulk the sole plate base. Wood for internal wall framing was delivered today woop woop! Hopefully will start on that next week, but need another pair of hands. Will have to see. Dan

Good ol' Dad helped me with the inner-leaf stud work. Half of it finished today, the rest we're doing tomorrow. :yahoo:

Update: Finished the inner leaf framing. Fixed ceiling joists in place. Fitted ventilation diffusers. I left one ceiling joist loose so I can lift the two inner leaf silencer boxes through into the cavity when they're done. I'll be putting those together next week hopefully. They're a new low profile design as they need to fit into around a 230mm cavity and not touch the outer leaf.

Today I made one of my inner leaf silencer boxes. These are alot bigger than the outer leaf ones. I needed them to be less than 210mm external height, and have the exit in the middle of the room over the diffusers. So my design splits the flow into two that run in parallel and then join back together as they exit the silencer.

Two words: Bad Ass. Greg

You might want to beef up this baffle with an extra layer of MDF: Right now, that single thin MDF panel is the only obstruction between the duct and the register. That's where your low frequencies will be getting through. It's the only thing attenuating the direct path, and it's not very substantial for that, so I'd suggest doubling up there. Apart from that, it looks great! - Stuart -

Thanks for your thoughts Stuart! Now that you mention it, I can see that happening. I'm afraid I've already fixed the lid, overlaid it with another 9mm mdf and had my father and brother in law help me lift it onto the joists! So it looks like I'll have to leave it anyway sadly. Hopefully the frequencies will meet their match in my outer leaf and silencer :lol: I've now got to add some noggins underneath the silencer to transfer the load to the adjacent joists too.

Gregwor wrote:

Two words: Bad Ass. Greg

It's cool right??

On second thoughts Stuart, I'm sure I could reach in through the hole underneath and beef up that section of it up from inside! I'll do that later in the build though. Remind me guys!

Duct fitted and silencer securely fixed in place. Dan

I've now got to add some noggins underneath the silencer to transfer the load to the adjacent joists too.

I'd put Sorbothane in there, to decouple it. Or neoprene. No solid connections! - Stuart -

Soundman2020 wrote:

I've now got to add some noggins underneath the silencer to transfer the load to the adjacent joists too.

I'd put Sorbothane in there, to decouple it. Or neoprene. No solid connections! - Stuart -

This silencer is for the inner leaf. It's already decoupled, there's a gap between it and the outer leaf. Where are you suggesting the sorbathane to go? Dan

Where are you suggesting the sorbathane to go?

It might be decoupled from the outer-leaf, but it is sitting directly on those inner-leaf joists. There are multiple turns inside, so there will be turbulence... turbulence = noise, likely low frequency, likely affecting the box itself. Vibration. Resonance. Decouple everything. Even if it looks like you don't need to, still decouple. Assuming you want maximum isolation, and the lowest possible NC.... :) - Stuart -

Soundman2020 wrote:

Where are you suggesting the sorbathane to go?

Not preserved: inner leaf silencer in place--decouple.jpg

It might be decoupled from the outer-leaf, but it is sitting directly on those inner-leaf joists. There are multiple turns inside, so there will be turbulence... turbulence = noise, likely low frequency, likely affecting the box itself. Vibration. Resonance. Decouple everything. Even if it looks like you don't need to, still decouple. Assuming you want maximum isolation, and the lowest possible NC.... :) - Stuart -

I had considered decoupling the silencers but decided against it, as my TL requirements aren't huge and the air velocity will be quite low. How would you go about attaching the silencer to the joists without coupling them? Using neoprene/sorbathane bolts?

I've been thinking about the possibility of decoupling the silencer. I'll get some adhesive backed neoprene sponge rubber. I can get it in a roll of 10m x 12mm x 10mm. I can line the tops of the joists with it and sit the silencer on it. Resilient brackets look good for attaching the silencer to the joists. I can screw the bracket into the side of the box and then into the top of the joists. Dan

I'll get some adhesive backed neoprene sponge rubber. I can get it in a roll of 10m x 12mm x 10mm. I can line the tops of the joists with it and sit the silencer on it. Resilient brackets look good for attaching the silencer to the joists. I can screw the bracket into the side of the box and then into the top of the joists.

Sounds like a plan! - Stuart -

Had some time today so started on the second low-profile silencer. I added the additional thickness to the baffle you mentioned this time Stuart too! Dan

:thu: - Stuart -

Hi Dan, It's looking brilliant so far, I'm enjoying reading your thread. I'm in the UK too and I've got the frame up, cladded and the roof felted. I'm building my inner leaf first and will build my outer leaf at a later date. I wanted to pick your brains; right now I have a single layer of 18mm OSB on the walls and roof and, like you, I was going to beef up with 2 layers of 15mm plasterboard... until I read your idea of using cement board on the outside instead. This is a brilliantly tempting idea as it would save so much time. From what I gather, the cement board is weather resistant and can simply be painted, do you know if this is true? This is going on the outside of my INNER leaf, so I don't really want to spend extra money on external cladding as it will all be covered up once the outer leaf is installed. So, to clarify I would attach the cement board to the outside of the OSB, covering up the seams and fixing to the studs, and then seal all the gaps and joints. Would this cause any risk of trapping moisture in? I would still need to beef up my ceiling from the inside as the felt is already on, but at least it would save me some time. The cement boards I've been looking at vary between 12kg/m2 - 14kg/m2. So, plus the 18mm OSB I should end up with the equivalent mass or even a bit more than 2x 15mm plasterboard layers by themselves. Any advice, much appreciated! Paul

Paulus87 wrote:

Hi Dan, It's looking brilliant so far, I'm enjoying reading your thread. I'm in the UK too and I've got the frame up, cladded and the roof felted. I'm building my inner leaf first and will build my outer leaf at a later date. I wanted to pick your brains; right now I have a single layer of 18mm OSB on the walls and roof and, like you, I was going to beef up with 2 layers of 15mm plasterboard... until I read your idea of using cement board on the outside instead. This is a brilliantly tempting idea as it would save so much time. From what I gather, the cement board is weather resistant and can simply be painted, do you know if this is true? This is going on the outside of my INNER leaf, so I don't really want to spend extra money on external cladding as it will all be covered up once the outer leaf is installed. So, to clarify I would attach the cement board to the outside of the OSB, covering up the seams and fixing to the studs, and then seal all the gaps and joints. Would this cause any risk of trapping moisture in? I would still need to beef up my ceiling from the inside as the felt is already on, but at least it would save me some time. The cement boards I've been looking at vary between 12kg/m2 - 14kg/m2. So, plus the 18mm OSB I should end up with the equivalent mass or even a bit more than 2x 15mm plasterboard layers by themselves. Any advice, much appreciated! Paul

Hi Paul, nice to see another UK studio builder! I'm struggling to visualise what you have at the moment. You say you have a frame up, roofed and cladded, but mention that your outer leaf will be completed at a later date. Is the cladded frame and roof not your outer leaf? Cement board is designed to be an external skin yes and weatherproof, but should really be rendered over if exposed to the elements for more than 6 months or so. You could seal the cement board by rendering the joints and painting it yes. This is an example of the board I'm talking about: https://www.insulationshop.co/aquapanel_exterior.html Dan

Waka wrote:

Paulus87 wrote:

Hi Dan, It's looking brilliant so far, I'm enjoying reading your thread. I'm in the UK too and I've got the frame up, cladded and the roof felted. I'm building my inner leaf first and will build my outer leaf at a later date. I wanted to pick your brains; right now I have a single layer of 18mm OSB on the walls and roof and, like you, I was going to beef up with 2 layers of 15mm plasterboard... until I read your idea of using cement board on the outside instead. This is a brilliantly tempting idea as it would save so much time. From what I gather, the cement board is weather resistant and can simply be painted, do you know if this is true? This is going on the outside of my INNER leaf, so I don't really want to spend extra money on external cladding as it will all be covered up once the outer leaf is installed. So, to clarify I would attach the cement board to the outside of the OSB, covering up the seams and fixing to the studs, and then seal all the gaps and joints. Would this cause any risk of trapping moisture in? I would still need to beef up my ceiling from the inside as the felt is already on, but at least it would save me some time. The cement boards I've been looking at vary between 12kg/m2 - 14kg/m2. So, plus the 18mm OSB I should end up with the equivalent mass or even a bit more than 2x 15mm plasterboard layers by themselves. Any advice, much appreciated! Paul

Hi Paul, nice to see another UK studio builder! I'm struggling to visualise what you have at the moment. You say you have a frame up, roofed and cladded, but mention that your outer leaf will be completed at a later date. Is the cladded frame and roof not your outer leaf? Cement board is designed to be an external skin yes and weatherproof, but should really be rendered over if exposed to the elements for more than 6 months or so. You could seal the cement board by rendering the joints and painting it yes. This is an example of the board I'm talking about: https://www.insulationshop.co/aquapanel_exterior.html Dan

Thanks for the reply, yes that’s similar to the board I’ve been looking at. It’s a toss up between about 5kg/m2 more of mass and lots more work vs less work and slightly less mass... but with the added benefit of protecting my osb. Yes my build is a little unusual, I’m building the inner leaf first and it’s an inside out design, so that’s why it is already cladded and roofed on the outside of the frame. I’m doing it like this for budget reasons as it will allow me to have a useable, albeit sound leaky, space that I can at least move my gear into instead of it being stored, and it’ll be good enough to use for teaching and light mixing. Thanks for your help, can’t wait to see your progress

Paulus87 wrote:

Waka wrote:

Paulus87 wrote:

Hi Dan, It's looking brilliant so far, I'm enjoying reading your thread. I'm in the UK too and I've got the frame up, cladded and the roof felted. I'm building my inner leaf first and will build my outer leaf at a later date. I wanted to pick your brains; right now I have a single layer of 18mm OSB on the walls and roof and, like you, I was going to beef up with 2 layers of 15mm plasterboard... until I read your idea of using cement board on the outside instead. This is a brilliantly tempting idea as it would save so much time. From what I gather, the cement board is weather resistant and can simply be painted, do you know if this is true? This is going on the outside of my INNER leaf, so I don't really want to spend extra money on external cladding as it will all be covered up once the outer leaf is installed. So, to clarify I would attach the cement board to the outside of the OSB, covering up the seams and fixing to the studs, and then seal all the gaps and joints. Would this cause any risk of trapping moisture in? I would still need to beef up my ceiling from the inside as the felt is already on, but at least it would save me some time. The cement boards I've been looking at vary between 12kg/m2 - 14kg/m2. So, plus the 18mm OSB I should end up with the equivalent mass or even a bit more than 2x 15mm plasterboard layers by themselves. Any advice, much appreciated! Paul

Hi Paul, nice to see another UK studio builder! I'm struggling to visualise what you have at the moment. You say you have a frame up, roofed and cladded, but mention that your outer leaf will be completed at a later date. Is the cladded frame and roof not your outer leaf? Cement board is designed to be an external skin yes and weatherproof, but should really be rendered over if exposed to the elements for more than 6 months or so. You could seal the cement board by rendering the joints and painting it yes. This is an example of the board I'm talking about: https://www.insulationshop.co/aquapanel_exterior.html Dan

Thanks for the reply, yes that’s similar to the board I’ve been looking at. It’s a toss up between about 5kg/m2 more of mass and lots more work vs less work and slightly less mass... but with the added benefit of protecting my osb. Yes my build is a little unusual, I’m building the inner leaf first and it’s an inside out design, so that’s why it is already cladded and roofed on the outside of the frame. I’m doing it like this for budget reasons as it will allow me to have a useable, albeit sound leaky, space that I can at least move my gear into instead of it being stored, and it’ll be good enough to use for teaching and light mixing. Thanks for your help, can’t wait to see your progress

So if I understand you right, currently you have a frame installed with OSB3 on the outside (you've called this cladding in your post?) and roof joists on top, that are boarded (presumably with OSB3 too and felted. And that's where you're at. Correct? You plan to use this as an inside out inner leaf in future by building a new timber frame all around this not touching the frame you have now, including a new roof over the top and adding mass and facing it all. Am I on the same page now?

Waka wrote:

Paulus87 wrote:

Waka wrote:

Paulus87 wrote:

Hi Dan, It's looking brilliant so far, I'm enjoying reading your thread. I'm in the UK too and I've got the frame up, cladded and the roof felted. I'm building my inner leaf first and will build my outer leaf at a later date. I wanted to pick your brains; right now I have a single layer of 18mm OSB on the walls and roof and, like you, I was going to beef up with 2 layers of 15mm plasterboard... until I read your idea of using cement board on the outside instead. This is a brilliantly tempting idea as it would save so much time. From what I gather, the cement board is weather resistant and can simply be painted, do you know if this is true? This is going on the outside of my INNER leaf, so I don't really want to spend extra money on external cladding as it will all be covered up once the outer leaf is installed. So, to clarify I would attach the cement board to the outside of the OSB, covering up the seams and fixing to the studs, and then seal all the gaps and joints. Would this cause any risk of trapping moisture in? I would still need to beef up my ceiling from the inside as the felt is already on, but at least it would save me some time. The cement boards I've been looking at vary between 12kg/m2 - 14kg/m2. So, plus the 18mm OSB I should end up with the equivalent mass or even a bit more than 2x 15mm plasterboard layers by themselves. Any advice, much appreciated! Paul

Hi Paul, nice to see another UK studio builder! I'm struggling to visualise what you have at the moment. You say you have a frame up, roofed and cladded, but mention that your outer leaf will be completed at a later date. Is the cladded frame and roof not your outer leaf? Cement board is designed to be an external skin yes and weatherproof, but should really be rendered over if exposed to the elements for more than 6 months or so. You could seal the cement board by rendering the joints and painting it yes. This is an example of the board I'm talking about: https://www.insulationshop.co/aquapanel_exterior.html Dan

Thanks for the reply, yes that’s similar to the board I’ve been looking at. It’s a toss up between about 5kg/m2 more of mass and lots more work vs less work and slightly less mass... but with the added benefit of protecting my osb. Yes my build is a little unusual, I’m building the inner leaf first and it’s an inside out design, so that’s why it is already cladded and roofed on the outside of the frame. I’m doing it like this for budget reasons as it will allow me to have a useable, albeit sound leaky, space that I can at least move my gear into instead of it being stored, and it’ll be good enough to use for teaching and light mixing. Thanks for your help, can’t wait to see your progress

So if I understand you right, currently you have a frame installed with OSB3 on the outside (you've called this cladding in your post?) and roof joists on top, that are boarded (presumably with OSB3 too and felted. And that's where you're at. Correct? You plan to use this as an inside out inner leaf in future by building a new timber frame all around this not touching the frame you have now, including a new roof over the top and adding mass and facing it all. Am I on the same page now?

Almost - apart from there’s only one layer of osb on top of the roof rafters. So yes the whole building is a frame with osb layer on the outside of the frame. On top of that osb layer I want to install the cement board, apart from the roof where I will install it on the inside between the rafters. The roof is a double pitched roof. You can see my design and build thread here: viewtopic.php?f=1&t=21409

Ah cool, I can't believe I've never noticed your thread! Yep the cement board can be installed over your OSB3 fine. Make sure you screw straight through the OSB into your studs. When placing your vapour control membrane, in the UK we usually put it just before we plasterboard a room. So all the insulation is behind the vapour control layer and a breather membrane is attached to the outside the OSB before you face it. By using cem board though you won't need the breather membrane (you won't benefit from it's breathableness due to the cem board being sealed air tight anyway. So when you fit your outer leaf you will need to attach a breather membrane to the outside of that if you clad it. Dan

Waka wrote:

Ah cool, I can't believe I've never noticed your thread! Yep the cement board can be installed over your OSB3 fine. Make sure you screw straight through the OSB into your studs. When placing your vapour control membrane, in the UK we usually put it just before we plasterboard a room. So all the insulation is behind the vapour control layer and a breather membrane is attached to the outside the OSB before you face it. By using cem board though you won't need the breather membrane (you won't benefit from it's breathableness due to the cem board being sealed air tight anyway. So when you fit your outer leaf you will need to attach a breather membrane to the outside of that if you clad it. Dan

Great, that's what I was thinking. I'm guessing I would have the option to either clad or simply paint the outer leaf if I also used cement board for that? So here's a very crude sketch just to clarify: