Attic Shaped Studio

#196

Nice one! They bring the workpieces up to a good height to work on too.

I think this was one of the videos I viewed. Probably nothing new for experienced woodworkers like yourself here Starlight, but it might be useful for some others viewing the thread. Guidance for saw horses starts about 7:00, and there is loads of useful info about circular saw use before that. For example he mentions setting the blade depth to a 1/2 tooth below the cutting depth of the workpiece. I always used to have it set to maximum.

https://www.youtube.com/watch?v=dRau7aaR2c4

Cheers!
Jennifer

#197

Two 20kg weight plates pushed all the way to the back for a total load test of 40kg. Didn't move at all.

Once the OSB border is attached all the way round these traps I'll add a bit more.

Cheers!
Jennifer

#198

That's a pretty good load for a start anyway!

Regarding tools, I agree entirely about the importance of the right tools to make the job easier. Like many of you I own (well part own) a cheap table saw and with a bit of bodging it can do a sensible cut. I bought a new sliding mitre saw with stand before this project which has been invaluable, and the nail guns certainly made the outside build much quicker. The funny thing is the best things I've bought have been a work platform for £45 that is about 90cm long so I can work on the ceiling etc without going up and down ladders, and a set of quick release clamps.

Jennifer I wondered if there was a concern around the screws that are holding these in place just going into the end face of the OSB on the trap? That looks to be a weak point - have you any plans to further fix these?

Cheers
Gareth

#199

garethmetcalf wrote:Source of the postJennifer I wondered if there was a concern around the screws that are holding these in place just going into the end face of the OSB on the trap? That looks to be a weak point - have you any plans to further fix these?

Good point, thanks for the reminder. I had wondered about that too, and thought about washers for the screws subject to the greatest pull from the cantilever force, i.e. those along the top row of the traps. There would presumably be an equal but opposite force on screws going into the joists near the floor.

On the other hand, the screw heads are huge though, and seem to be holding up really well. Putting washers in would require some countersinking to allow a flush fit of the plasterboard over the OSB. Therefore the OSB would have to be thinner around the point of force... hmm.

Perhaps I'll do a couple of washer types as well in each trap for a belt & braces approach :-)

Cheers!
Jennifer

#200

Hi
Good points but that’s not what i meant, sorry. I was thinking about the wood that the thread of the screws is attaching to in the bass traps, as it looks like the screws are going into the 18mm thick edge of the OSB... does that make sense? Am I right? If so I can imagine that much like chipboard the screws don’t have much purchase on the wood??

I’m sure you’ve got it under control though!

Gareth

#201

Aha, I see what you mean now. Yes, the screws are going in to the 18mm thick edge of the OSB, I also joined the traps together in this way. The screws seem to hold very securely indeed, I don't think any of them have stripped the thread in the wood yet despite immense tightening.

I used 100mm long screws for securing the top edges of those traps to the wall OSB, so they are anchored pretty deep.

I'll add more load to one of the wider traps tomorrow and see what happens

Cheers!
Jennifer

#202

Here's some further explanation about how in the absence of ability to compute the cantilever loads for those traps mathematically, I proceed with a measure of confidence they will be ok. By comparison to other real world loads on similar structures.

I've already mentioned the kitchen cabinet analogy. Here's another, my chinup bar, currently surrounded by project materials :idea:

The grip protrudes about 47cm from the wall, and from this grip an adult human being (average 80kg if you are in North America) can hang. The load will increase and decrease with movement of the exercise. That's a significant cantilever force, and the bar is rated for heavier than that. It's screwed in to a block wall here, but would also work on a stud wall. It is utterly solid. My previous chinup bar attached to a door frame, for example.

This is of course a live rather than dead load, so the comparison is not exact. But it does give some notion of just how strong these house structural elements are.

Cheers,
Jennifer

#203

Got all the traps fitted in place today except for the one second from the left. Nearly 9.30pm, too late to start sawing the OSB surround parts for that now after a long day.

#204

WOW! That looks fantastic!

#205

Agreed! As you’ve said previously these will make for great storage should the room not be a studio in the future. It’s almost a shame to fill and cover them.

#206

Thanks chaps. Indeed, and the extra amount of space they seem to add to the room is quite surprising to me too, given they are only 60cm deep. Still, the extra space will be there acoustically, and that's what counts in large amounts!

#207

If these were being kept as storage, I'd make the floor of them continuous with the room floor by having a tiny wooden "step", something like this. It seems to make the room look bigger;

But that is not to be. Instead it will be a false wall made of fabric, so I installed an OSB "lip" to pin the skirting board to. A layer of plasterboard will be applied to all the OSB before that though.

Most of the sealing is done, what a job!

#208

No doubt you’ll wish you bought a cordless sealant gun before too long. One of the best recommendations from this forum for sure!

#209

garethmetcalf wrote:Source of the post No doubt you’ll wish you bought a cordless sealant gun before too long. One of the best recommendations from this forum for sure!

No doubt indeed! They look well handy. Alas, I have already exceeded the budget for this project, and then some

Just have to soldier on with the good old fashioned one!

#210

Since the built in bass traps are in a stable state, I went back to the ventilation part today. Time to tear down the plasterboard knee wall on the exhaust / fan side and hope the silencer design will fit.

Zoinks Scooby!

The good news is that all the electric and signal cable routing is manageable. The massive relief news is those radiator pipes are not attached to anything or terminated, so can be trimmed back to allow the silencer to fit. The stud frame is a bit weedy and will need replaced or beefed up to hold the silencer.

Here's what I was hoping for - silencer the same as on the supply side;

Alas, unlike the supply side, there is a house structural cross beam in the way, marked in red. So the design won't fit. Bah!

The only way round this I can think of that fits into the same constraints is to reduce the silencer from 3 baffles to 2, and lower the hose a bit to get closer to the "end corner". It means the sound will be going round less corners, so presumably attenuation won't be as good. However, the hose exits on the side of this silencer rather the end (like on the supply silencer) so perhaps a little more attenuation might be gained from this?

Perspective is called for here. All I have to match is the attenuation of the inner leaf before the exhaust duct enters the eaves (which have a ventilated deck), so it doesn't have to be amazing. Additionally, as part of the soffit build I intend to put a plenum onto the silencer going into the room via the side of the soffit. It will act as part of the silencer. It will have double the cross section of the silencer, giving another impedance change, and also turn another corner, so perhaps will bring it close to the performance of the supply silencer?

Comments welcome as ever, cheers folks!

Soundman2020 - Studio Design Forum