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

Hi Stuart, Yep this is all inner leaf (you must have missed the pictures of it being framed). The plasterboard about to be installed is the inner surface of the room. Dan

So the inner-leaf is NOT being built inside out? Which is what you said a while back? So if the walls are not being built inside-out, then the walls are OK, but no matter which way you build the ceiling now (inside-out or conventional), it is not OK. If you are going with an inside-out ceiling, then the plastic should all be on top of the joists, not wrapped around the underside. Your ceiling modules would then press up against it, and you would be able to seal the modules to the joists, correctly. With the plastic there, you can't do that. And if you are going with a conventional ceiling (not inside-out) then there is going to be an air gap above the drywall. So either way, it is not correct. - Stuart -

The ceiling is the only inside out surface in my design. The walls are conventional. Hmm... I hadn't considered that sealing the ceiling modules would be affected by wrapping the vapour barrier around the timber. I wonder whether this could be addressed without having to change the membrane. The reason I wrapped it under in the first place was because it was almost impossible to get the membrane over the joists without messing up the insulation. I'm going to look into a way to seal the inner ceiling modules even with the membrane there. My fall back option could be to "box in" the joists by lining them all with a layer of plasterboard, which is then sealed against the ceiling modules. Dan

After taping my vapour membrane joints, I started with the OSB on the walls. One of the short walls and two corners are fixed in place.

I got some help today and managed to fit the rest of the OSB sheets on the walls. I've done 75% of the space between the joists. So after I've finished that, I've got to put some little squares of OSB beneath each joist and caulk it all. Next jobs : The ceiling modules > caulk > box in the joists (as the vapour barrier is around the joists) > screed the floor to smooth it off > wall plasterboard. Dan

How is your HVAC working so far?

Hi Greg, It's not been installed yet. The electrician is coming when I've finished the walls (he needs a surface to surface mount to :wink:). So he'll wire the ventilation at the same time. Then the AC guy will install the mini - split. Dan

Then the AC guy will install the mini - split.

You probably already know this, Dan, but it doesn't hurt to remind: the bundle of pipes and wires that link the indoor unit to the outdoor unit cannot run directly across your wall cavity in a straight line, for obvious reasons... I hope your HVAC guy is aware of that? - Stuart -

Hi Stuart, I was aware of that. I am considering the best method of achieving this. I assume they can just add a couple of 90° bends to the pipe work right? I've not fully fixed the OSB yet, I've just screwed it in place. So I'll be able to remove a section to put that pipework in. That has reminded me that he does still need to come back and put the pipework in before the OSB is finished. Thanks Stuart. Dan

I assume they can just add a couple of 90° bends to the pipe work right?

You can't bend the HVAC pipes very much, only very gentle curves. If you try to bend it too tight, it will kink. One way to do it is to have a gentle curve across nearly the entire wall cavity depth, then run the pipe bundle parallel to the wall surface across at least one stud bay (preferably two), then curve it gently back the other way, to go through the outer leaf. Make the second penetration a little lower than the first, so that the condensate pipe slopes down always, never up (unless your AHU has a condensate pump on it). - Stuart -

Thanks Stuart, I'm not doing the work myself, but I'm going to be there to let him know what's acceptable to maintain sound isolation and reseal the vapour barrier and put the OSB in place when the pipes /wires are in. He's been good, he's going to chat to me about later so I'll pass on the info you gave me. I'm waiting for the electrician to drop off the SWA, so I can put it through the (offset) entry point and reseal and put the OSB over it. Then he'll come and wire everything once the plasterboard is done. When it comes to caulking the entry points, I'm using flexible conduit. Does this method sound good: I caulk around the outside of the conduit first to fill the hole, then caulk all around the wires in the conduit once they're fixed in place? I'll keep you guys updated. Thanks, Dan

Question about locking my external door. I need to lock the studio (for obvious reasons) and I'm thinking of the best way to do that whilst also meeting safety regulations. I'm required to be able to unlock the door from the inside without a key (makes sense). My plan: Internal door: No latch, no lock, door closer holds tight against the seals. Surface mounted handle in room, push plate in cavity. External door : Surface mounted handle on the outside, push plate in cavity. A single dead bolt in the center of the door with external key and internal thumb - turn, like this: No latch, door closer holds door tight against seals when in use. The deadbolt doesn't need a big hole being cut and it seems to place a large amount of steel through the holes it needs. I understand I need to be careful not to get caulk in the mechanism when fitting this. Have you guys got any other/better suggestions?

I caulk around the outside of the conduit first to fill the hole, then caulk all around the wires in the conduit once they're fixed in place?

Sort of, but it needs a bit more than that. Yes, caulk around the outside of the conduit on both sides of the drywall, but then when the wires are in placed, push a piece of slightly twisted-up insulation down the end of the conduit, as far as you can get it (twist it up into a long thin worm shape), and allow it to untwist and expand again to fill up the gaps around the wiring, then caulk over the end of the conduit, and maybe a 1/4" inside. That way, if you need to replace the wires in the future, or add more wires, you can pull off the caulk fairly easily, then fish out the insulation. Also, when you run the wires, always leave an extra piece of "fish tape" in the conduit for the same purpose: so that you can pull through new wiring if you have to. By the way, I usually don't use flexible PVC conduit, as it is very light weight, and brittle. I use ordinary electrical conduit, heated up then bent into shape. That conduit has thicker walls, and is tougher. I also terminate it in a distribution box with a cover plate, on the room end of the conduit, and caulk around that too. It's certainly not the same mass as the drywall, but it's the best you can do.... unless you feel like using metal conduit! :shock: - Stuart -

The deadbolt doesn't need a big hole being cut and it seems to place a large amount of steel through the holes it needs.

Yep, that should be fine. As long as there's plenty of mass, and you seal the end plates well, that will work. - Stuart -

Hey guys, I've got some more pics for you! I've put in the cables etc. for the electrician, and caulked the outside of the conduits but not around the wires yet incase he needs extra length etc when installing. I'll do that when he's finished. The AC guys came to install the pipework today. The engineer was good and took on board the information I gave him about studio needs. An example: usually they put a continuous run of lagging through the hole in the wall with the pipe, I explained that lagging has no mass so he agreed to terminate the lagging at the hole and I caulk the hole and then continue lagging inside the cavity. So I was glad I was home to keep on top of it. We ended up agreeing on the pipe work running down inside the cavity between the leaves with the outer leaf hole about 1m below the inner leaf hole. The two copper pipes and condensate hose as well as the cable all went through the one hole. I wish the hole could have been a little smaller though, so I'll have to use a ton of caulk to seal it. I think I'll surround the pipes in the hole with backer rod and caulk both sides in stages maybe, to allow the first layer to cure before adding another layer of caulk. Sound good? Pics!

Bad ass! That hole is no match for a ton of caulk! You'll be good to go for sure! Greg

The holes are all caulked and dry now, the OSB is secured and the bottom gap is caulked and drying. The cool thing is, the leveling compound will provide additional mass over the caulk and raise the floor height a few mm. So now, when I attach the plasterboard, the gap underneath will be a little offset giving a really good floor to wall seal. My Dad is coming to level the floor for me either tomorrow when I'm working or Saturday morning. I'll keep you updated dudes.

Floor leveled. Ceiling modules started!

Spent the day building frames for the ceiling modules. 6 more left to build (more materials arriving tomorrow morning) Two layers of 15mm plasterboard to go on top of each module. Dan

Sorry for the delay in posting updates guys. I've made some progress. The ceiling modules are all finished. Most of them are installed. I've plasterboarded all of the walls, caulked my corners and a plasterer skimmed them yesterday. It's finally starting to look like a room. 8) Next jobs: Friday I'll be installing the last of the ceiling modules and caulking them. Then boxing in all of the joists with plasterboard. A couple of coats of white emulsion on the walls, then the electrician and AC guys can come finish their jobs. 8)

Cut the module for the ceiling ventilation outlet. Without the fan on its got a really nice draft coming through the hole. A nice blast of air as I cut the membrane over it. It's got good flow of air but not rushing, which is a good sign. 8) Is not central which was annoying but I wanted the diffuser to be central on the ceiling, so it's a bit offset and twisted, but hey ho it's covered by the diffuser... No one will eeeever know. I lined the hole with the same neoprene strip I used to decouple the silencers, about 20mm away from the hole all around, then I pushed the ceiling module up tight against the neoprene, compressing it about 20%. I then pushed some backer rod in and will caulk the gap. I might use some powder filler, at some point, around the cut edge of the plasterboard to stop plaster dust and bits breaking off. Dan

Some progress was made on my ceiling. I've fitted all of the plasterboard strips and caulked half of it. Caulking takes a ton of time. You wouldn't expect how much! I've still got to put the plasterboard strips along the bottom face of each joist, but needed to get the modules done so the electrician can come in and put the ceiling cabling in for the ceiling track lighting. I'll still be able to put my insulation around the cabling once it's in so that's good. Dan

I'm so excited to see how much transmission loss you've achieved with your awesome build! Great work man! Greg

Gregwor wrote:

I'm so excited to see how much transmission loss you've achieved with your awesome build! Great work man! Greg

Thanks Greg! It'll be great to see. I'm a little uneasy about the transmission loss though as I didn't have the exact right thickness of wall insulation and didn't want to compress it in, so there was a little void of about 25mm. I thought it would be fine and sealed everything up, but am having pangs of regret everytime I see the gap in between the leaves where the second door is going :? I'm hoping it will be fine though :D. I'm making sure to not lose heart and get complacent with the caulking though. So we'll see. Painting the walls today. Mist coat is dry, it's ready for the second coat now so gotta get working 8) Larch cladding is ordered, with a 4 to 6 week lead time :shock:. Track lighting is ordered and arrives Tuesday. Waiting for the electrician to get back to me with a date. I'm waiting for a forecast of good weather over a weekend next, so I can get my doors made up and fitted. More pics will be on their way soon enough. Dan

As promised, some pictures. I've got to caulk some more of the ceiling modules and around the top of the walls. I've painted the walls white as a base, and will decide what colour to finish them in after I've finished the speaker baffles and the rear wall treatment. It's really brightened up the studio having the white though! Dan