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How long does it take to DIY install insulation?


Thorfun

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I know this is a 'piece of string?' type question but I know that a few on here have installed their own insulation (@ProDave is the first name that springs to mind) so I was wondering if anyone could give a rough estimate on how long it'd take one man (with assistance from SWMBO) to install insulation in a timber frame?

 

I'm talking about 140mm mineral wool between the studs and a layer of 50mm or 80mm PIR on top. and then, while I'm at it, how long to then add an air tightness membrane on top of the PIR?

 

obviously it depends on the size of the house but I'm sure an average hr/m2 could be obtained with enough results!

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Last one I did we did with the walls lying down, dead easy to stand them up, building was 12m x 20m single storey 2.4m high, all insulation batts, sheet insulation and vapour barrier 2 days three men -  add a bit for walls standing up - take off a bit as we stood our walls up too  

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Only the walls or do you have slopes and ceilings to consider? Our build is similar, but with the membrane under the PIR. Our walls were meant to be factory insulated but issues in the plant meant that they came to us bare and a squad was sent in to carry out the stuff/membrane/PIR/batten to all the external walls (we'd always expected to do the slopes and ceilings ourselves...)

Between 2 and 4 men and over a few full days and a fortnight of long evenings as I recall, for 250m2 or so. Guessing 200 man-hours maybe?

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34 minutes ago, dpmiller said:

Between 2 and 4 men and over a few full days and a fortnight of long evenings as I recall, for 250m2 or so. Guessing 200 man-hours maybe?

If you paying men to do it - maybe spray in foam insulation might be a good alternative 

I was quoted £30sq m for  closed cell foam sprayed in for equivalent of 140mm PIR -open cell is cheaper  -that would be after first fix -job done in a day usually

and it will make house totally air tight -which is not certain with other types 

get a quote would be my suggestion ,unless you already bought all the insulation

 might be an option 

Edited by scottishjohn
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37 minutes ago, dpmiller said:

Only the walls or do you have slopes and ceilings to consider? Our build is similar, but with the membrane under the PIR. Our walls were meant to be factory insulated but issues in the plant meant that they came to us bare and a squad was sent in to carry out the stuff/membrane/PIR/batten to all the external walls (we'd always expected to do the slopes and ceilings ourselves...)

Between 2 and 4 men and over a few full days and a fortnight of long evenings as I recall, for 250m2 or so. Guessing 200 man-hours maybe?

thanks for the response. I'm considering the walls and the roof. we have a vaulted ceiling as well for the entrance hall which is 2.8m wide.

 

200 man hours, wow. so for me on my own on evenings and weekends I'm looking at about 6 weeks or so just for the walls.

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5 minutes ago, scottishjohn said:

If you paying men to do it - maybe spray in foam insulation might be a good alternative 

I was quoted £30sq m for  closed cell foam sprayed in for equivalent of 140mm PIR -open cell is cheaper  -that would be after first fix -job done in a day usually

and it will make house totally air tight -which is not certain with other types 

get a quote would be my suggestion ,unless you already bought all the insulation

 might be an option 

 

I'm not 100% convinced of the spray foam as I want the sound insulation and decrement delay qualities of mineral wool (or wood fibre) in between the studs and then the PIR over that to reduce the cold bridging of the timber studs.

I'm also trying to reduce our oil based insulation and having 140mm of it in the walls just seems very un-green!

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It's hard to estimate how long it took, because I did it as we go with cladding etc.

 

Our build was a little unusual. The insulation went in as the wood fibre exterior insulation went on so the insulation got fitted as the cladding went on so none was exposed.  That job took weeks (not continuously) as we clad a wall at a time then got it rendered

 

cladding_1_small.thumb.jpg.4f96c42e061bb5cb0bd3bee9a4617020.jpg

 

Then inside, when doing the ceilings, the insulation was fitted from the inside, then OSB then battens then plasterboard.  So done a room at a time or even a half room at a time

 

roof_insulation_8.thumb.jpg.e3187bc4fbb34efae40dcb5480a5b199.jpg

 

I used Knauf Earthwool Frametherm 35.  It is stiff enough to push in between the rafters and just stay there (I left a test piece for 6 months and it did not move or fall out) and is possibly the least bad of the mineral wool type if insulation to handle.

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5 minutes ago, ProDave said:

It's hard to estimate how long it took, because I did it as we go with cladding etc.

 

Our build was a little unusual. The insulation went in as the wood fibre exterior insulation went on so the insulation got fitted as the cladding went on so none was exposed.  That job took weeks (not continuously) as we clad a wall at a time then got it rendered

 

I used Knauf Earthwool Frametherm 35.  It is stiff enough to push in between the rafters and just stay there (I left a test piece for 6 months and it did not move or fall out) and is possibly the least bad of the mineral wool type if insulation to handle.

 

Thanks Dave. I have to admit it doesn't look like a hard job and is certainly something that I can do. my only concern is in the loft but as we're hoping to go attic truss rather than Fink truss I will have the space up there to be able to work in reasonable comfort.

I'm really struggling to justify the cost that some TF manufacturers charge for the installation of the insulation. I guess you're paying for the reduced time it takes to do it. but with the money I can save it will pay for quite a lot of other stuff.

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8 minutes ago, ProDave said:

I have been building on a stupidly small budget, so doing everything I possibly can and taking a long time has been a must.

I'm not sure SWMBO will allow that for me! so it's finding a nice compromise between saving money and being in the new place before we're old and grey. ?

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On 05/06/2020 at 12:02, Thorfun said:

[...] a layer of 50mm or 80mm PIR on top. and then, while I'm at it, how long to then add an air tightness membrane on top of the PIR?

 

Why not use the PIR as the air tightness layer..?? Just tape with foil tape, ceiling join would need to be done carefully but not difficult.

 

Could be as simple as using 25mm as the first layer held in with 25mm battens, then back fill the gaps and tape. That would thermally break the timber frame also from the inside and give you battens to fix the plasterboard into.

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20 minutes ago, PeterW said:

 

Why not use the PIR as the air tightness layer..?? Just tape with foil tape, ceiling join would need to be done carefully but not difficult.

 

Could be as simple as using 25mm as the first layer held in with 25mm battens, then back fill the gaps and tape. That would thermally break the timber frame also from the inside and give you battens to fix the plasterboard into.

 

no reason in particular for doing as you say. I was just trying to mimic what seems to be the standard wall make-up of a number of TF manufacturers. I also actually like the idea of the membrane adding an extra layer of airtightness even after the PIR has been taped. and then batten on top of that to create the service void. it makes for a thicker wall but it just appeals to my sense of neatness. also means I don't have to cut PIR to size to fit the battens which I'm trying to avoid.

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18 minutes ago, PeterW said:

 

Why not use the PIR as the air tightness layer..?? Just tape with foil tape, ceiling join would need to be done carefully but not difficult.

 

Could be as simple as using 25mm as the first layer held in with 25mm battens, then back fill the gaps and tape. That would thermally break the timber frame also from the inside and give you battens to fix the plasterboard into.

Is there not something you can get  like car body underseal,but not bitumastic ,as that would melt foam maybe 

 builders foam would do ,but would be very messy i think 

that you could just spray all the gaps and joints with a shutz gun .seems like a gap inthe market if  no one makes something very quick to to do 

I would worry that foil tape over time might come away from the studs  you stick it to-

 

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Just now, Thorfun said:

also means I don't have to cut PIR to size to fit the battens which I'm trying to avoid.

thats the point ,you need to make them good fit -time consuming,  or they will loose insualtion value as well as being leaky

 which is why alot go for bats as they more tolerant of fit

any holes in membrane need to be sealed as would electrical boxs etc --any penetration of membrane

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2 minutes ago, scottishjohn said:

thats the point ,you need to make them good fit -time consuming,  or they will loose insualtion value as well as being leaky

 which is why alot go for bats as they more tolerant of fit

any holes in membrane need to be sealed as would electrical boxs etc --any penetration of membrane

exactly! ?

hence the wall make-up I've chosen. 

it's figuring out how long it'll take me that's the issue as it's not something I've done before.

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I used celotex in a 140mm timber frame - it took a long time.  Next time its going to be a similar build as @ProDave.  I used plastic sheets & tape to make it all air tight - thats Q quick tbh (need two pople to install - one to hold the sheet & one to staple it in place raedy for taping.

 

Good luck

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1 minute ago, CC45 said:

I used celotex in a 140mm timber frame - it took a long time.  Next time its going to be a similar build as @ProDave.  I used plastic sheets & tape to make it all air tight - thats Q quick tbh (need two pople to install - one to hold the sheet & one to staple it in place raedy for taping.

 

Good luck

thanks. I'll have a second pair of hands as the lovely wife is willing to get involved so that's not an issue.

 

I've read a lot of threads on here about the nightmare that people have had installing PIR between the frame studs and so I'm dead against doing that! and now I have even more reason thanks to your experiences.

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not self build I mean PIR.  With enough time to forget the pain I might use PIR again.  It is good insulation with min space taken up.  Ours is not a simple house shape and that didn't help the job.

 

Have fun

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