Extension- Last Stuff.

[PeterW]

It just squashes down and comes back when you take the board off so stop worrying. You won’t damage anything. 
 

You need as much as possible up there - get the layers in ..!!

[A_L]

1 hour ago, zoothorn said:

I cannot see anything there, there's not even a '100mm' figure, and I dont see any notes..

 

Referring to Note 1.

 

For a wall, insulation between studs, 200mm of unbranded loft  roll (Thermal Conductivity 0.044W/m.K) is needed

For the ceiling 300-350mm are required dependent on exact configuration

 

 

 

Edited December 17, 2020 by A_L
typo

[Onoff]

A squirrel sh!t and nut shell combo makes an excellent insulator. Don't block the holes up and it'll build up/get warmer over time...

 

Maybe! ?

[zoothorn]

36 minutes ago, A_L said:

 

Referring to Note 1.

 

For a wall, insulation between studs, 200mm of unbranded loft  roll (Thermal Conductivity 0.044W/m.K) is needed

For the ceiling 300-350mm are required dependent on exact configuration

 

 

 

 

I'm still stumped. I thought the point in Q was the rigid stuff in the sloped ceiling-? 100mm or thereabouts, I'm roughly sure.

 

I'm not understanding any of the table stuff I'm afraid, but am I meant to?. But thanks for efforts to help.

[dpmiller]

"roughly sure" isn't good enough.

[zoothorn]

1 hour ago, PeterW said:

It just squashes down and comes back when you take the board off so stop worrying. You won’t damage anything. 
 

You need as much as possible up there - get the layers in ..!!

 

Yup understood- my board does go a bit bendy in middle you see. Its gonna be a helluva struggle getting anything else in tho tbh even with board across joists.

 

One other thing: the leccy cables: they do a loop up & over, in series etc. I've seen clips whereby its said to bring them up on top out the way.. but its innevitable some will be within the insulation, actually a fair bit, esp if I'm going super thick adding my 3rd layer/ much will  be immersed.

[zoothorn]

14 minutes ago, dpmiller said:

"roughly sure" isn't good enough.

 

No dpm, this is why I'm asking if anyone knows what this figure is!

 

Im given a table, but there's nothing on there, a bible with pg 16 Im told to look at, but nothing on there either.

 

Surely someone would just know. 100mm? 75mm? 125mm? Its likely to be one of these, 140mm of rigid is just too thick for any ceiling area, if I've been told to put 140mm in the walls.

 

Anyway I can't be responsible for any shortcomings my builder might have built it to. If it should be 100mm, and BCO measures 75mm.. then builder has to come back. Same with general loft stuff I'm at least 8sqm short (if not another full 16sqm of 100mm too).. but as I need to crack on/ as I'm cold/ I can't wait for BCO.

[ProDave]

10 minutes ago, zoothorn said:

One other thing: the leccy cables: they do a loop up & over, in series etc. I've seen clips whereby its said to bring them up on top out the way.. but its innevitable some will be within the insulation, actually a fair bit, esp if I'm going super thick adding my 3rd layer/ much will  be immersed.

The cables should either lie on the ceiling with the insulation on top, or the cables should be on top of the insulation.  The cables should NOT end up in between 2 layers of insulation.

[dpmiller]

7 hours ago, zoothorn said:

 

 

Anyway I can't be responsible for any shortcomings my builder might have built it to. If it should be 100mm, and BCO measures 75mm.. then builder has to come back

 

 

The BCO isn't coming back, won't be measuring it, and the builder won't be fixing it. But you will live with a cold room unless you work out what should've been done and check what was done.

If the room was warm, none of this would matter; but you've got a problem and you're currently trying to diagnose it.

[Big Jimbo]

I've been away, but missed your posts Zoot the Hoot. Hope you are keeping well, if perhaps still cold ? What your builders have done, is what they have done. You will have to tackle any insulation issues yourself now fella. Poor insulation, badly done, is an issue so often seen on site. It's only the end user that really cares fella, as they are the ones paying the heating bills, and feeling bloody cold. With a bit of care and attention, even if you can't get it perfect, i'm sure you will be able to make it much better. Some of your skills so-far have surprised a few of us.

[zoothorn]

11 hours ago, ProDave said:

The cables should either lie on the ceiling with the insulation on top, or the cables should be on top of the insulation.  The cables should NOT end up in between 2 layers of insulation.

 

Hi ProDave- understood. But if I only have so much 'loop'/ slack between the 4x downlights, if I put in 300mm worth of fluff, the cables have no choice but be -mostly- covered by it. I'll only be able to lie the 'top of the loop' on the surface. And if I go 350mm, then its all buried for sure.

 

So what do I do?

[zoothorn]

3 hours ago, dpmiller said:

 

 

The BCO isn't coming back, won't be measuring it, and the builder won't be fixing it. But you will live with a cold room unless you work out what should've been done and check what was done.

If the room was warm, none of this would matter; but you've got a problem and you're currently trying to diagnose it.

 

The BCO surely is coming back if he's got to sign it off. He hasn't even seen the pB & electrics job yet/ hasn't been in since the builder left exactly a year ago when he ticked his boxes off as it were/ so I could pay & be done with him.

 

All I know is along this one sloped side, 100mm of PIR is in, albeit not very well afaict.. but I cant access it to change it.

[A_L]

12 hours ago, zoothorn said:

I thought the point in Q was the rigid stuff in the sloped ceiling-? 100mm or thereabouts, I'm roughly sure

 

O.K. , assuming the 'rigid stuff' is PIR or similar and the timber holding up the ceiling plasterboard does not fully penetrate the insulation i.e. there is at least 50 mm of insulation covering the timbers then 150mm should be sufficient, see attached table. If the insulation is fully penetrated by timber, creating a thermal bridge, then 200mm between the timbers will be required.

 

 

[zoothorn]

150mm?? PIR?? 200mm?!?

 

So this is more than the 140mm PIR I was told to put in the timber frame inner wall. But that doesn't compute.

 

I'm not sure if your point is telling me what the B.regs stipulate (I still cant glean any info from this table, bar '100mm thickness' so I'm also unsure where 150 & 200mm figs even come from), or if your suggesting what I now have to do is approach my builder to tell him he needs to come back/ add 50mm, or approach my BCO & ask him to tell builder to.. or, if you're implying I have to top up the 100mm I find, by min 50mm, somehow, in order to satisfy myself that the cold isn't coming in here.

 

I haven't got a clue what these tables, and posts surrounding them, are for/ what points is being made relative to the thickness figures.

[ash_scotland88]

Out of curiosity did zoot ever post drawings or plans for the extension?

Apart from this possible not enough insulation I'm wondering if there's a physical/design reason why the room may be colder.

[A_L]

12 minutes ago, zoothorn said:

But that doesn't compute.

 

It does compute, from Table 2 walls only have to achieve U=0.28W/m².K but ceilings have to achieve 0.18W/m².K. That implies 56% more thermal resistance (insulation).

 

21 minutes ago, zoothorn said:

I'm not sure if your point is telling me what the B.regs stipulate

 

B regs stipulate a max U-value, as in Table 2, which insulation and thickness you use to achieve it is up to you

 

23 minutes ago, zoothorn said:

I haven't got a clue what these tables, and posts surrounding them, are for/ what points is being made relative to the thickness figures.

 

Sorry, in that case you need to find someone who does

 

25 minutes ago, zoothorn said:

in order to satisfy myself that the cold isn't coming in here.

 

Cold is always coming in, it is just the rate that we control with insulation 

 

[zoothorn]

53 minutes ago, A_L said:

 

It does compute, from Table 2 walls only have to achieve U=0.28W/m².K but ceilings have to achieve 0.18W/m².K. That implies 56% more thermal resistance (insulation).

 

 

B regs stipulate a max U-value, as in Table 2, which insulation and thickness you use to achieve it is up to you

 

 

Sorry, in that case you need to find someone who does

 

 

Cold is always coming in, it is just the rate that we control with insulation 

 

 

 

Ok thanks A_L. I'm not exactly sure where this info leaves me.

 

It may be possible these two PIR pieces are in fact 75mm tho.. I cant get near enough to get a measure on (& looked to me like 50mm Ive use alot/ under caber floor etc). I'll try squeeze in but Im quite fat might get stuck. only the squirrel could rescue me then.

[zoothorn]

1 hour ago, ash_scotland88 said:

Out of curiosity did zoot ever post drawings or plans for the extension?

Apart from this possible not enough insulation I'm wondering if there's a physical/design reason why the room may be colder.

 

I did to the builder & to BCO both happy- & we did discuss this sloped area, after BCO telling me a figure he told builder to put in (I recall as I was surprised it was thick'ish PIR). But as to exact fig he said, I just went with it being a him + builder talk, not my having to note then AND 'check' as it was being built (not knowing it'd be impossible to access, even once a hatch put in).

 

You do put a certain ammount of trust in your builder- altho I admit I knew he was stringing me along at this stage in other areas, so it could be he hasn't put in what he should. But even so, if 100mm in, as I know to be minimum, instead of 150mm, its not going to be the sole reason I can only ever get the room warmed to 17.9* max, however long the huge rad is on.

 

 

[ash_scotland88]

6 minutes ago, zoothorn said:

 

I did to the builder & to BCO both happy- & we did discuss this sloped area, after BCO telling me a figure he told builder to put in (I recall as I was surprised it was thick'ish PIR). But as to exact fig he said, I just went with it being a him + builder talk, not my having to note then AND 'check' as it was being built (not knowing it'd be impossible to access, even once a hatch put in).

 

You do put a certain amount of trust in your builder- altho I admit I knew he was stringing me along at this stage in other areas, so it could be he hasn't put in what he should. But even so, if 100mm in, as I know to be minimum, instead of 150mm, its not going to be the sole reason I can only ever get the room warmed to 17.9* max, however long the huge rad is on.

 

 

I've looked through your posted topics and from an "in progress" thread it looks like you extension downstairs has a small hallway separating the new downstairs room and the wall of the old house. While the upstairs room abuts directly to the old stone wall of the cottage. Is this correct?

 

If so, and those that may understand these principles better than me, could the cold 4ft thick cottage wall be acting as a giant heatsink, or even a "coldsink"? It's a big old thick bit of stone that is taking a lot of energy to heat up while constantly being re-cooled from the outside and coldness moves along its mass from outside to inside. This is then acting as a giant cold radiator in your room. You're not getting this downstairs as you have that small hallway separating the new room and the old stone wall, here you have 4 newly highly insulated walls there and only 3 upstairs.
My house, a 1950s semi with cavity wall insulation, I can feel a very small change of temperature from the corner of an internal and external wall to the middle of the internal wall, it's colder towards the exterior wall. Infact my kitchen, which is like your extension has three external walls,  the shared internal wall is colder to the touch than an internal wall say in the lounge.

 

If my theory is correct, and happy to be corrected, I would be looking at what the insulation is against the old cottage wall and if this is sufficient. Even if a damp barrier was installed, and even though it may not show physical signs of damp, stones are great for drawing it out the atmosphere and passing it along to each other (and dampness I found always make the air feel colder.). An internal cavity up here may even be the way forward, or you may just need time to allow what was a cold external wall (thats had hundreds of years to get that cold) to heat up to become a warmish internal wall.

[Declan52]

But what was put in the roof was both not enough plus was put in wrong with gaps everywhere. Heat rises and your ceiling insulation was plain crap. If it's all escaping out the roof it won't matter how long you run your heating or how big the rad is, the room won't get warm enough.

All the insulation is doing is being Tom thumb holding back the water only your ceiling is Tom new born baby wee finger. It's just not capable of doing it. All the insulation is doing is slowing the rate at which it will leave your house. There is always going to be some leakage your just getting it down as low as you can. You need to roll more out end of. 300mm min depth. You can lie across the insulation it won't compress enough to burst through the ceiling. 

Buy some cheap ass clay pots and cut a notch out of the lip with a grinder or hacksaw if you don't have one for the cable going to your downlights. Silicone around the edge of the pot and fill in the notch so it's sealed to the plasterboard.  This will stop cold air leakingn in plus heat escaping. You just need to get this done as soon as before the really cold months come or before we all lose the will to live and go out licking shop door handles in the hope of getting covid. It's not a big job just a messy one. Buy enough rolls to finsh the 100 mm between the joists and then another 200min above that. Go online and look at the coverage in each pack and use the room measurements to figure out what you need to finish it off.

Stop stressing about what the builder did and didn't do it's not getting you anywhere. Realistically he's been paid so if you ask him to come back and fix it he's going to tell you where to go. So go to your builders yard/homebase/b&q and buy what you need to buy and get the job done. Finger out and get it sorted for this weekend.

[zoothorn]

Hi @ash_scotland88 thanks for casting your opinion/ reading my stupidly long thread! (Im a newbie/ amateur, hence takes me 6x to understand stuff, let alone 10x to build it).

 

I've thought of your 'coldsink' idea (PeterW also has this opinion) but alas I have to correct you: in fact the lower room (directly below) -doesn't- have such a hallway. So it has the same wall (old end of house) as one of its 4 sides, just as the room above. In fact, both similar in area too. So the sort of mystery is, to me anyway, why if the lower room has a rad in half size of room above,  & with all 4 walls similar, why is this lower room super toasty.. but room above totally different/ cold. Yes the lower room is 250mm lower; but has a rad half the size, and a big (obvious) weak point too: it has a cheap pine door opening to the outside, that's not even airtight (I go in/out of 20x a day too).

 

Anyway I need to cross off the 'doables' 1st, the loft undoubtadly 1st, esp if I find a 4ft area of bare pB up there, where my spark didnt bother pulling the insulation back over (undid a pB section for access, to fit 4 downlights). The 2nd being the door yet to make for top room: this doorway, unlike room below, goes into the adjacent master bedroom (a knock-thru created in old end wall).. a blanket up temporarily here, which tantalisingly, has made a bit of difference (like 1*). Balancing rads 3rd, in case this huge rad isn't putting out what it should.

 

Then if these 3 don't work.. I'm up a gum tree (& tbh I might have to call it a day, just always will be a cold'ish room.. like all other rooms are, bar the toasty workshop!). Lining the end wall is 4th.. but loathed to, 1) bc of space intrusion/ lessening, 2) the character gone, 3) the work/ mess/ logistics to do it (& 4) it might it not be the cold cause anyway, if lower rooms seems ok).

 

The other side of

[zoothorn]

@Declan52 spot-on advice as always.. that's very helpful/ I was wondering if a notch needed in me pots. I'll certainly try putting in what I can, now I'm reassured about squashing the fluff down/ not ruining my pB ceiling.

 

I just have the nagging thing about the cables: whether they'll determine now how much extra fluff I can put in, if its paramount they lie ontop of it, I assume its only mostly so (some will innevitably have to pass thru & up, and some within the fluff too/ skirting along a joist or so).. it cannot all go ontop, even as I have it now call it 200mm.

 

I'm gonna aim for 300, try for 350. Much appreciated- zH

[A_L]

@ash_scotland88,makes a very valid point. If as it seems from the 'in progess' thread you have a heated volume through the original wall there will be no heat loss over its area but you will have a very significant thermal bridge at the points where the new extension walls and ceiling meet the original wall. The heat shortcuts through the original wall to the outside.

 

That not withstanding I favour @Declan52 's position that poorly fitted board insulation allows 'thermal bypass', air movement from outside to inside (or reverse) and this is the major heat loss. Board insulation simply lying on plasterboard is inadequate. It should be tightly fitted to the timber or loose enough to use foam around the edges of the board.

[ash_scotland88]

@zoothorn cheers for coming back and correcting me. Looking at your pictures posted I thought there was a door entrance next to the old cottage with a timber stud wall going in to block it off, creating that hallway space.

 

It sounds like you have a bunch of stuff to check first, to rule out possible issues. Checking insulation/adding more and trying to figure out why the radiator isn't getting as hot would be the top of my priority.
Have you went back to basics and checked the thermostatic valve is correctly working on the big rad upstairs? Is the pipe going to the radiator feeling the same as the pipe in the room below?

[zoothorn]

5 minutes ago, A_L said:

@ash_scotland88,makes a very valid point. If as it seems from the 'in progess' thread you have a heated volume through the original wall there will be no heat loss over its area but you will have a very significant thermal bridge at the points where the new extension walls and ceiling meet the original wall. The heat shortcuts through the original wall to the outside.

 

That not withstanding I favour @Declan52 's position that poorly fitted board insulation allows 'thermal bypass', air movement from outside to inside (or reverse) and this is the major heat loss. Board insulation simply lying on plasterboard is inadequate. It should be tightly fitted to the timber or loose enough to use foam around the edges of the board.

 

Its poorly fitted on the sloping side, yes there might be bits even missing.. just have to hope not. There will definitely be gaps here, but I cannot remedy this. But if the lower room door is considered, opening to outside, with gap under door, frame poorly stopping the cold too.. & this room's toasty even so.. then a bit of inadequacy/ gaps can still mean a toasty room.

 

Have to see what this loft insulation redo does to the room. I guess proof's in the pud.. my thermometre's there ready.