Continuous insulation, something I’m most impressed with.

[Cabinetman]

So as you may know I’m insulating the inside of my old barn to create a workshop and after looking into different methods I decided to use the continuous insulation method where the insulation goes on top of the studs, there are pros and cons, you lose some internal space but this method is very much quicker and there is virtually no thermal bridging through the studs to the outside.



You can of course also fill in between the studs, but I soon realised that it’s time consuming to cut and then go around each piece with squirty foam.
I am putting Three layers of 1 1/2” rigid insulation onto the old studs, I am putting them on so that the joints don’t overlap and rightly or wrongly I have decided to only put squirty foam between the joints on the outer (weather) layer. My reasoning is that that will stop any draughts getting through from the outside and as long as the sheets butt up tightly all will be well.
So on top of the three layers there are 6 horizontal Furring strips, I hadn’t come across them before but am most impressed, they cinch down the rigid foam nice and tight and give me something to fasten the plasterboard or whatever to.
It does mean that very long screws are needed, large plastic washers are used on the first two layers to hold the boards still and flat till the last layer goes on and is held in place by the Furring strips.
The strips are usually 3” x1” but the amount needed would be pretty expensive so I’m using 2x4’s cut into 4 each piece is roughly 1 1/2” x 3/4” this is by far the most cost effective way over here. And If I can’t manage to hit those when fitting the plasterboard there’s something far wrong! But to aid in this I’ve prepared a baton with the measurements on, simply stand it on the floor and it shows where they are.
Fastening the 8 ft strips was challenging till I came up with pushing a row of 4” nails into the insulation to rest the far ends on whilst lining up with the mark and screwing it down.


Pic showing the 4” nails, 4” 5” and 7” screws plus the plastic insulation washers, also shown is a bit of the marker batton which will eventually be hung on the wall for future use and a made up section of the final wall which I’ve found handy for working out the reveals around the windows etc.
Working around a gas pipe, grrr.

 

[duke]

I'm sure your neighbours wont be hearing any machine noise

 

[Cabinetman]

I'm sure your neighbours wont be hearing any machine noise

Very true, tested it in my last but one workshop with the saw and the planer going and it was minimal, plus this time the neighbours are a great deal further away!

 

[Mike G]

Excellent, Ian. Butt joints like yours are perfectly OK. I only use (and specify) foam if it's between bits of wood (studs, joists, rafters, or teardrop frames). What's happening above the top edge of the wall insulation?

 

[Doug]

It works really well Ian, I’d did the same many years ago on a chapel conversion all the external walls were wrapped & taped internally with insulation prior to a stud frame being constructed in front of the insulation to true up the walls.

It’s a lot of work but definitely worth the effort

 

[Cabinetman]

It works really well Ian, I’d did the same many years ago on a chapel conversion all the external walls were wrapped & taped internally with insulation prior to a stud frame being constructed in front of the insulation to true up the walls.

It’s a lot of work but definitely worth the effort

View attachment 54051

That’s an interesting way of doing it, I hadn’t thought of that! And here was me thinking I was doing something unusual.

 

[Cabinetman]

Excellent, Ian. Butt joints like yours are perfectly OK. I only use (and specify) foam if it's between bits of wood (studs, joists, rafters, or teardrop frames). What's happening above the top edge of the wall insulation?

Oh good! I have a sketch which I’ll have to find, come back to you.
Ian

 

[Cabinetman]

Sorry the sketch is god only knows where.
Going upwards, 2x8” coach screwed to the studs with 2x8’s in joist hangers on 16” centres, three small bits of insulation between the joists to fill in the “pockets” then three layers of insulation forming a floor on top of the joists, with plasterboard under to form a ceiling. It gets cold and pretty hot here do you think 4 1/2” will be enough?
Ian
(Edit to change bolts to screws)

 

[Accipiter]

My next-door neighbour has been having a new roof put on his home. I was somewhat surprised to see the roofers using some 4"/100mm 'brown' boards. Asked about it and they said it's a woodfibre insulation, 1200 x 380 fitted between the rafters then covered over again with larger - but thinner (various thicknesses available - tongue & grooved fibre insulation. Supposedly water proof! I wasn't aware that this sort of stuff was in use - only aware of the foam type boards.

Your workshop is going to be a cozy place Ian ️

 

[Mike G]

........three small bits of insulation between the joists to fill in the “pockets” then three layers of insulation forming a floor on top of the joists, with plasterboard under to form a ceiling........

That sounds like 9" altogether (4-1/2" between the joists, plus 4-1/2" over). That's loads. That's approximately equal to 18" of fibreglass/ mineral wool. You'll be fine with that. Take particular care with the junctions (ie where ceiling meets wall), and with services (electrics and any plumbing).

 

[Cabinetman]

That sounds like 9" altogether (4-1/2" between the joists, plus 4-1/2" over). That's loads. That's approximately equal to 18" of fibreglass/ mineral wool. You'll be fine with that. Take particular care with the junctions (ie where ceiling meets wall), and with services (electrics and any plumbing).

No sorry I’ve not described it very well, it’s only at the ends between the joists against the header? That the little bits go in, the rest of the space between the joists is open so just 4 1/2” over the workshop in total. Is 4 1/2” of rigid enough?

 

[Cabinetman]

My next-door neighbour has been having a new roof put on his home. I was somewhat surprised to see the roofers using some 4"/100mm 'brown' boards. Asked about it and they said it's a woodfibre insulation, 1200 x 380 fitted between the rafters then covered over again with larger - but thinner (various thicknesses available - tongue & grooved fibre insulation. Supposedly water proof! I wasn't aware that this sort of stuff was in use - only aware of the foam type boards.

Your workshop is going to be a cozy place Ian ️

I do hope so! After this last winter which was brutally cold I need it. Came across those fibre boards recently but it seemed a bit expensive, and I don’t think it’s waterproof but who knows.

 

[Mike G]

Is 4 1/2” of rigid enough?

Yes, for a workshop.

 

[Accipiter]

I do hope so! After this last winter which was brutally cold I need it. Came across those fibre boards recently but it seemed a bit expensive, and I don’t think it’s waterproof but who knows.

I snagged an offcuts from them and have left it outside - if slightly under cover. It's had some rain on it and doesn't seem to be breaking down as I was expecting. The roofers do cover it over with the membrane then batten and fix the tiles so guess it doesn't matter to much

 

[duke]

So as you may know I’m insulating the inside of my old barn to create a workshop and after looking into different methods I decided to use the continuous insulation method where the insulation goes on top of the studs, there are pros and cons, you lose some internal space but this method is very much quicker and there is virtually no thermal bridging through the studs to the outside.
View attachment 54048


You can of course also fill in between the studs, but I soon realised that it’s time consuming to cut and then go around each piece with squirty foam.
I am putting Three layers of 1 1/2” rigid insulation onto the old studs, I am putting them on so that the joints don’t overlap and rightly or wrongly I have decided to only put squirty foam between the joints on the outer (weather) layer. My reasoning is that that will stop any draughts getting through from the outside and as long as the sheets butt up tightly all will be well.
So on top of the three layers there are 6 horizontal Furring strips, I hadn’t come across them before but am most impressed, they cinch down the rigid foam nice and tight and give me something to fasten the plasterboard or whatever to.
It does mean that very long screws are needed, large plastic washers are used on the first two layers to hold the boards still and flat till the last layer goes on and is held in place by the Furring strips.
The strips are usually 3” x1” but the amount needed would be pretty expensive so I’m using 2x4’s cut into 4 each piece is roughly 1 1/2” x 3/4” this is by far the most cost effective way over here. And If I can’t manage to hit those when fitting the plasterboard there’s something far wrong! But to aid in this I’ve prepared a baton with the measurements on, simply stand it on the floor and it shows where they are.
Fastening the 8 ft strips was challenging till I came up with pushing a row of 4” nails into the insulation to rest the far ends on whilst lining up with the mark and screwing it down.

View attachment 54050
Pic showing the 4” nails, 4” 5” and 7” screws plus the plastic insulation washers, also shown is a bit of the marker batton which will eventually be hung on the wall for future use and a made up section of the final wall which I’ve found handy for working out the reveals around the windows etc.
Working around a gas pipe, grrr.

View attachment 54049

Ian , I notice some 15 and 20 amp cable running behind your walls, Is this for your outlets or are you bringing down surface mount BX or wire in a conduit?