Garden Recording/Mixing Room in Surrey, UK - Build Diary

#91

That's rather disappointing! It's hard to say if it could have due to the stacked mineral wool, but the "damp" pattern does seem to roughly match the locations where the packages were, from what I can see, so I guess it is a possibility. Was there any moisture in or on the packages when you removed them?
Is there any chance that this could be coming up through the slab from below?
I'd wait to see if it dries out fully, then do the "plastic square" test: cut out a large square of thick clear plastic, and tape it to a section of the slab that you suspect, using duct tape (it won't stick very well probably, but well enough). Leave it a couple of days and see if any condensation forms under the plastic. If it does, then that suggests water still in the slab from somewhere. If you don't get any sign of condensation, then that would indicate that the slab is dry, and you are probably OK.

- Stuart -

#92

It takes concrete a long long time to cure and dry completely. Months even. If you stored these bats on the slab for any extended period of time, it is likely that moisture from the curing process has risen up from the slab and gotten trapped between the plastic and the concrete. Ill bet $1 that once it dries out, you never see it again.

Also, did you pack the cavities with drywall in addition to having 2 exterior layers of OSB or was the 2 exterior layers of sheathing in lieu of 2 layers of drywall in between the studs? Just curious.

#93

Soundman2020 wrote:Source of the post That's rather disappointing! It's hard to say if it could have due to the stacked mineral wool, but the "damp" pattern does seem to roughly match the locations where the packages were, from what I can see, so I guess it is a possibility. Was there any moisture in or on the packages when you removed them?
Is there any chance that this could be coming up through the slab from below?
I'd wait to see if it dries out fully, then do the "plastic square" test: cut out a large square of thick clear plastic, and tape it to a section of the slab that you suspect, using duct tape (it won't stick very well probably, but well enough). Leave it a couple of days and see if any condensation forms under the plastic. If it does, then that suggests water still in the slab from somewhere. If you don't get any sign of condensation, then that would indicate that the slab is dry, and you are probably OK.

- Stuart -

I didn't notice any moisture on the bottom of the insulation packs when moving them as it was done without noticing the damp.

re' if it is coming up from under, I have no idea, I simply can't see how it is possible, what with the DPM underneath the insulation, under the concrete base. I have always been really careful not to compromise the DPM.

And As I mentioned, I dug down in the soil on the corner where moist floor is and checked the DPM from the outside, expecting there to be water trapped in the corner when pressing/tapping it, but it feels/sounds bone dry.
I've tried the plastic square section, but can't get any tape to stick properly. I did get the edges held down with heavy wood but, after 2 days nothing was under the plastic. It's all very strange. Perhaps it was just the storage of the insulation.

eightamrock wrote:Source of the post It takes concrete a long long time to cure and dry completely. Months even. If you stored these bats on the slab for any extended period of time, it is likely that moisture from the curing process has risen up from the slab and gotten trapped between the plastic and the concrete. Ill bet $1 that once it dries out, you never see it again.

Also, did you pack the cavities with drywall in addition to having 2 exterior layers of OSB or was the 2 exterior layers of sheathing in lieu of 2 layers of drywall in between the studs? Just curious.

Thanks eightamrock. I'd like to see a bigger wager to rest my mind, but I'll take it

The Concrete was laid 4/5 months before the insulation was then stored on it, so I would have thought it would have cured. However, we did get quite a bit of rain after the concrete was laid, so there could have been extra water that needed to come out.
Hopefully it's nothing to worry about.

No drywall in the cavities. That's just the external leaf; I'll be installing a 2nd leaf soon. (room inside a room)

#94

The Concrete was laid 4/5 months before the insulation was then stored on it, so I would have thought it would have cured.

Concrete never really cures 100%. The process is called "hydration", and continues for years, even decades (according to some). After a couple of days, it's good to walk on safely. After a week, it's good for light loads. After a month, it's good for serious loads. After three months it is getting as close to being as good as it's going to get, strength wise, but is still hydrating. The general rule is to allow 28 days for each inch of thickness before loading it fully.

It also depends on HOW you cure it: if you don't keep it moist at all initially, then it is at maximum strength within about a month or so. If you keep it moist for a few days, then it reaches a higher maximum strength after about 60 days (but still not fully hydrated). If you keep it moist for a month, then it reaches an even higher maximum strength after about 90 days. If you keep it moist indefinitely, it keeps on reaching ever higher strength levels for a long, long time. Here's a graph showing how that works:

But even when it has reached maximum strength, the hydration process can still be going on, very slowly, for a long time. As long as that is going on, there is still unbound moisture in the concrete, which might be able to make it to the surface. Very little, of course, but there can be some.

This is also partly why new slabs crack: due to not being kept wet for long enough.

That's why you often see construction sites watering or misting the concrete slabs for many days, and often even with large plastic sheets over it: to keep the moisture in, so it cures more slowly, and thus attains higher strength

So, if you stacked the insulation while the concrete was still relatively fresh, then basically you kept the moisture in for that section, which is actually a GOOD thing (assuming that's what it is). The trapped moisture means that that part of the slab has higher compressive strength, because it was kept moist for a long time.

I'd let it dry some more, and see how it goes after the next heavy rain. If it remains dry even after a long downpour, then you are probably OK.

- Stuart -

#95

Haven’t had a chance to do a diary update as things have been busy, but I have been making progress.

What with all this hot weather, the concrete appears to have dried, and with not much rain hard to see if it is fixed but there is no new dampness, which is good, and of course I have to press on with the build… Also, I really don't know what I can do if water is somehow rising up through the slab. I spent half a day digging up around that corner on the outside to check the DPM as fas as I could go down, and apart from a very small (which I repaired) there was no other obvious way it could be getting in. I'll be putting some more DPM under the internal underlay/word floor in the studio anyway.

Day 564 (April 23’)

Made a start on installing the inline fan, ducting and grilles. Went with the TD500 in the end as it would just fit above the soffits (with cutting away some of the roof insulation) as you can see it is tight and I was worried about access once the cladding was on but thankfully it worked out ok. Cutting the holes for the ducting in those joists was very hard, not a job I would like to do again, without a Multitool it would have taken far longer; brilliant tool!

Of course the grilles did not fit the 200mm > 150mm reducers and the ‘bird mesh’ on the back of them was pretty pointless for insects so, as usual, I had to improvise with some nylon mesh.

Complete outlet Grille

#96

Day 578

With the Grilles and fan install complete...

I could move to getting the Siberian Larch cladding installed and the exterior of the studio complete. Once installed I used a product suggested by the cladding supplier (https://www.silvatimber.co.uk/sansin-woodforcetm) that is supposed to protect and help weather the cladding to consistent grey; we shall see.

using the cladding for the window frame returns provided a nice 'feature' with the groove side out, I was happy with the results. Silicon was added after to seal the gaps on the inside.

It was a lovely feeling to have finally completed the exterior of the building and I think the hybrid solution of metal for the unseen walls and sexy cladding for the front was a happy medium, aesthetically and financially. At least it's not an eyesore for the neighbours now

#97

Day 583 (June '23)

Time to move back to the interior of the studio and start on the inner leaf whist waiting for the Structural Engineers to approve my design for a module style inner ceiling.

Realised I didn’t post a pic of the internal stud walls once insulated with the fluffy stuff, so here it is just prior to installing the moisture barrier.

#98

Day 583 - 588 cont'...

This week saw me taking a week off work to focus on the build and get as much done as I could.

After sealing the gaps between sole plates of all outer leaf walls, I began cutting the moisture barrier into the sections for the walls and attaching to the outer studs with staples. Cloth tape was used to join the sections and finish the door/window cuts.

In this top pic you can just about see where I had to cut one roof joist (on both sides of room) to allow the silencer boxes to fit once the ceiling is in. I used noggins to provide extra support to this reduced joist on advice from experts.

Once I receive the rockwool, I will be placing in between the external roof joists and attaching more moisture barrier holding that in place which will then be joined to the wall DPM to create a complete seal of the room. I'll also be putting insulation in the stud bays above the walls.

#99

Day 585 - 588

Time to build and install the inner leaf walls. Doing this stuff on your own is hard but it’s amazing how we come up with ingenious ways of getting it done. My partner did some cutting of the timber on one of the days, which helped. She has been amazing and supportive throughout the build process, which I must admit has been stressful and seemed impossible at times.

Constantly moving the stuff around the makeshift timber shack is a real pain also, but as the materials are getting used, the stack is reducing, thankfully.

As I only realised after that the external wall bends in slightly at the front, the 25mm gap I had planned for was not going to be enough between leafs if I want the inner leaf front wall to be straight, so I extended the gap to 40mm all round, this stopped the plastic DPM from making contact with the inner leaf walls. I will use the ceiling joists to bring the walls straighter when attaching them. The actual slab is not completely level and the height of the walls in the corner near the door was unacceptably high, so I had to take it down and trim all the uprights again to get it more level. Took me a whole day to just connect the walls to each other and get the head plates to all line up as straight as possible. I mean, I’m just a keyboard tapper by trade, So I’m leaning.. a lot!

Again, was pretty pleased with what I have achieved this week. You can also see in the pics one of the silencer boxes, which I have nearly completed; here's a better pic:)

#100

I'm really concerned about this photo:

Those holes seem to be way too large, and in the wrong place, for structural integrity. You can cut holes in structural (load-bearing) beams and joists, yes, but they have to be done within certain limitations in order to not compromise the structural characteristics.

The normal recommendations are:

Your holes do not seem to comply. There is supposed to be at least 2" of wood on either side of the hole (above and below), for example, and the diameter of the hole should not be greater than 1/3 of the width of the beam/joist.

I'd strongly recommend that you get a structural engineer in to take a look at that, and see if you need to make any changes. It might be OK, depending on what loads, stresses and strains those beams are supporting, but I suspect not. There might be ways you can reinforce the areas where you did those holes to fix it, but that requires a qualified professional engineer to tell you, and that should be a local engineer from your areas, to make sure it also meets local building codes.

- Stuart -

#101

duplicate post deleted

#102

probably a bit late to the party here -- typically the best method to route the ducts AFTER the silencer, is in a ceiling soffit rather than risk structural issues in the ceiling joists. the soffits provide in room routing of ducts, wiring, accent lighting etc as well as significant absorption. agree with Stuart -- you need someone to look at those cutaways, you might be able to sister them with smaller openings which you can then expand the air volume in the register box for the vent. or as i mentioned - a ceiling soffit.

#103

Soundman2020 wrote:Source of the post I'm really concerned about this photo: holes-cut-in-beam.jpgThose holes seem to be way too large, and in the wrong place, for structural integrity. You can cut holes in structural (load-bearing) beams and joists, yes, but they have to be done within certain limitations in order to not compromise the structural characteristics.

The photo looks alarming, but may be deceptively so. At a second glance the holes through the joists are not on the part of the joist inside the building, but on the outside, under the exterior roof overhang. I have a notion of a memory that Beardmusic had these overhangs as an optional feature, i.e. not part of the load bearing structure, so perhaps drilling them in this way is ok? If not, perhaps reinforcement with a strong bracket would be sufficient? Caveat: I am not a structural engineer so what I'm saying may be completely wrong.

The single hole at 90° to those is going through the OSB outer leaf only, not part of the structure at all, so should be ok?

Cheers,
Jennifer

#104

Soundman2020 wrote:I'm really concerned about this photo: holes-cut-in-beam.jpgThose holes seem to be way too large, and in the wrong place, for structural integrity. You can cut holes in structural (load-bearing) beams and joists, yes, but they have to be done within certain limitations in order to not compromise the structural characteristics.

The normal recommendations are:
allowed-notches-and-hole-drilling-in-joists-2.jpg Your holes do not seem to comply. There is supposed to be at least 2" of wood on either side of the hole (above and below), for example, and the diameter of the hole should not be greater than 1/3 of the width of the beam/joist.

I'd strongly recommend that you get a structural engineer in to take a look at that, and see if you need to make any changes. It might be OK, depending on what loads, stresses and strains those beams are supporting, but I suspect not. There might be ways you can reinforce the areas where you did those holes to fix it, but that requires a qualified professional engineer to tell you, and that should be a local engineer from your areas, to make sure it also meets local building codes.

- Stuart -

Hi, Thanks for your concern, Stuart.

The cut outs for the ducting in the joists are basically identical to what Gareth did with his build here (viewtopic.php?p=4140#p4140); I saw no negative responses there?

However, I did research before cutting out the holes and could find nothing regarding cutting holes and notches after the load bearing stud walls on which the joists are sitting on. Joists can end at the point of the stud walls and overhang is not even required structurally. Even your picture/table shows what is allowed with the joists on the sections between the stud walls and shows the joists with no overhang. To clarify, these holes are past the outer leaf stud walls. The wide angle picture makes them look bigger than they are.

The only thing being supported by the overhang joist ends are the very front of the roof at that point, and I will make sure to not step there (going to mark it out with paint). In fact I will be going on the roof very rarely.

So, I’m pretty happy that it won’t cause an issue. As far as I know, Gareth’s roof has not fallen down as a result of the same holes.

Also, FYI: Building codes, or Building regulations in the UK only apply to outbuildings that have an internal floor area greater than 30m2. Mine is 27m2.

“If the floor area of the building is between 15 square metres and 30 square metres, you will not normally be required to apply for building regulations approval providing that the building contains NO sleeping accommodation and is either at least one metre from any boundary or it is constructed substantially of non-combustible materials.” - from https://www.planningportal.co.uk/permis ... utbuilding

Although my studio does not need to comply to building regulations, I have tried to build to that spec anyway as it makes sense to do so.

Cheers,

Sam.

#105

endorka wrote:Source of the post
Soundman2020 wrote:Source of the post I'm really concerned about this photo: holes-cut-in-beam.jpgThose holes seem to be way too large, and in the wrong place, for structural integrity. You can cut holes in structural (load-bearing) beams and joists, yes, but they have to be done within certain limitations in order to not compromise the structural characteristics.

The photo looks alarming, but may be deceptively so. At a second glance the holes through the joists are not on the part of the joist inside the building, but on the outside, under the exterior roof overhang. I have a notion of a memory that Beardmusic had these overhangs as an optional feature, i.e. not part of the load bearing structure, so perhaps drilling them in this way is ok? If not, perhaps reinforcement with a strong bracket would be sufficient? Caveat: I am not a structural engineer so what I'm saying may be completely wrong.

The single hole at 90° to those is going through the OSB outer leaf only, not part of the structure at all, so should be ok?

Cheers,
Jennifer

Haha, good to hear from you Jennifer! Hope all is well,

I missed your post when replying, confirming your guess

I think Stuart is trying to give me a heart attack, which with my stress level on this project is not needed

Soundman2020 - Studio Design Forum