0:00 Intro 0:17 Prep work 2:45 Solid vs Cavity Walls 3:54 Internal vs External insulation 5:26 Options for Internal Insulation 7:01 Building Regs & U-value 8:12 Options for Attaching Insulated Plasterboard 8:42 Attaching with Insta-Stik Foam 11:26 Mechanical fixings 11:56 Window Reveals 12:30 Finishing Touches 13:04 Outro

I've been using instastik for around 12 years, some tips would be to spray the board and wall with water prior to applying the foam, you get greater adhesion, apply foam between the edges of the boards to stop cold bridging. Also a more cost effective way is to use kingspan or similar board, then stick the plaster board to the kingspan. I've gone up-to 100mm kingspan with 15mm megadeco plaster boards. Bathroom walls have a load of around 100kg per 8x4 area that I have done. The key is a light waterspray for bonding and on old walls I use sbr bond on the walls. One last tip would be when sticking the plaster boards is when you butt them up together just twist a plasterboard screw between the sheets every 300-400mm the small amount of hold stops the sheet your sticking from expanding past the previous one and keeps them flush.

I seem to be following behind your life experiences in some regards, I used your videos to build my garden room 2 years ago, and when I just searched for 'sticking insulated plasterboard', up you popped with the goods! 😅 Much appreciated, your videos are always well presented, informative and very very helpful.

Glad to have found more from you after following your Garden Workshop Series! Great blend of instruction and rationale.

Nice tutorial and analysis. I had damp issues in my Victorian house in the alcoves so built a stud wall with 50mm gap from the wall then celotex insulation and plasterboard. I also vented behind the stud wall with holes in the suspended floor and going up through the ceiling and the same above. I found that I didn't need a plasterer by carefully filling all gaps with caulk then polyfiller to level, cross lining with lining paper and using a top layer of textured paper. If the costs of heating keep going up, I may sacrifice more interior space with another layer of insulated plasterboard!

Amazing. Two videos that will be of great interest as in the coming months as i have both these jobs to do. 👍🏻

Been using it for over 10 yrs.brilliant stuff

A great, detailed and informative video. Thanks for posting!

I'm looking at doing exactly this once I move into my new place and in all my research hadn't seen the foam as an option. Always helpful to see well presented alternatives, thanks!

Nicely explained, really competent analysis of interstitial condensation and well described. So many other diy dot and dabbers getting this wrong. Congratulations. (Ex architect and lecturer in construction technology)

You're a braver man than I removing that rad!! Great work

Great video mate. Very informative and great editing. Well done

Interesting video, very good how you give a run down of all the options and your reasoning. I live in a 1930's semi with solid brick walls, a few years ago I internally insulated all the of external walls with battens and 50mm of PIR insulation between in much the same way the walls in your garden room are constructed, and it has made a marked difference in the comfort level of our house as well as the heating costs, which are now significantly lower. It was however, a huge amount of work, especially as we hacked off all of the original lime plaster (it was loose it places anyway) to maximise room space. Keep up the good work!

Good video. Precise and to the point.

Amazing work and thanks so much for sharing your knowledge

Great job. Thank you for the time and effort you took to make this video and share it with us. Greetings from Croatia.

Excellent Ali. Really informative

Very well explained. Thank you 👍

Your videos are so good! Full of such good information. Well done 👏👏

Great video . I did a whole house like you’ve done here during a refurb. Insta-stik is incredibly strong. You can literally stick almost anything to anything and it’s not coming apart. It’s much quicker and cleaner than board adhesive dot and dab. You can get 2-3 boards from a can so it’s just slightly better value as well. It locks the wall boards to the ceilings, as the Victorian properties have mostly settled out of square and the inevitable gaps can be fully filled and locked together for the plasterer to tape over. No movement cracks later. But you need to bear in mind that the foam will continue to push a bit for quite a few minutes after it’s stuck the board, so care needs to be taken not to get a step against the adjacent board. It looks and smells like low expansion foam but it’s unbelievably strong once it’s cured. It can be tempting to use it where you shouldn’t really. It’s excellent on skirtings and architraves as well. No drilling and filling. Much much better than no-nails.

A nice video with great information. Subscribed.

Great video, about to undertake the same job in my own house

I come from a construction background, started from the architectural design field up to PM on big jobs. I do alot of DIY at home myself as i have an understanding of how it all goes together considering i would usually specify it on drawings. Im too lazy to document my work but if i did, it would be exactly like this, well done, really like the attention to detail and numbers according to the manufacturer. Subbed.

great video and well detailed , thanks

I'm very interested to see whether this is still performing as desired after a couple of years. This is almost exactly what I need to specify for a job I'm working on, so it would definitely be good to know whether it worked out well.

I've only ever used mechanical fixing on insulated plasterboard, after seeing a job where it had been dot and dabbed with plasterboard adhesive and the plasterboard had later become detached from the polystyrene. I've always used 6mm sds drill, red plugs, then 65mm aluminium nails (which hold in plugs better than you'd imagine.) You have to use a bit of scrim over the nail heads due to the compressibility of the insulation, otherwise the heads may pop occasionally. But I must admit, this looks like a feasible solution that would be a hell of a lot quicker. I'll give it a go next time I have some to do.

I've started using this gun adhesive and I really like it. You need to be aware that the foam can slightly push out the plasterboard as it cures. Also, spray the board laying on the floor exactly as you did in the video. If you try to spray it onto the wall it just makes a big mess. You definitely need mechanical fixings if using this in a kitchen where they might be wall cabinets.

Good video! Curious to know if you saw any noticeable benefits since you completed the project a year ago and been through a winter to measure the difference before and after? Thanks , I’m thinking of doing the same .

Great video well Done 😊

Superb! I found Knauf technical to be really helpful when I was selecting the insulated board for our renovation. They were happy to provide a u-value calc and dew point analysis via email - no fee or anything. Great service.

Great work man, I ended up going the stud wall route using CLS16 and 50mm PIR with a 12.5mm board on. This was on a late 1800's property. I put strips of DPC on every timber that was touching the wall and had an air gap between the wall and insulation (about 10-15mm on average) I was surpised how much noise it actually cut out just by doing this let alone how warm it was.

Good video enjoyed it

Love the upgrade to flip flops when you might step on a gripper rod or staple 🤣

I build a sun room 7 years ago 6m by 5m,,windows on 2 sides and 2 sky lights (velux window) i have 300mmcavity walls , i got them pumped with insulation , and on the inside walls i put insulated plasterboard 12mm plasterboard with 35mm insulation, its very warm with one rad about 1.5 m long under a window and on on the wall about 300 mm wide and 1.5 m tall, the roof is a warm roof, worth every penny, and looks good too... great video man

Did this to our Victorian bedroom a few months ago! I had a few added complications, namely having to replace all the double glazing and dealing with a bay window. Cutting that insulated plasterboard at a perfect angle is quite the challenge! Otherwise you did pretty much the same as me. Great work.

super helpful

Pajama renovating...intriguing

I did a baton frame of 2x1’’ with 400mm centres with 50mm kingspan filling. Then put a visquin sheet across the whole wall to stop moisture, then plaster board.

Such a useful vid, thanks Ali. Anyone see any issues with tiling over this type of system? with the extra fixings it should be plenty strong enough for a grout and tile finish in a bathroom right?

Thanks for making this video, I've found it really useful. How many canisters of insta-stick did it require for a wall this size?

Great video Ali, I'm thinking of doing this to my downstairs bathroom external wall as they get really cold. Do you know if you can have the U value of the wall checked by a builder or building Regs at all? I believe the wall is already insulated but I was going to add another 50mm with foil/backed/foam/plasterboard wondering if that would suffice? thanks John

You need to pull up (or cut) the floorboards at the wall to be insulated and insulate between the timbers using PIR. The cold bridge on the uninsulated bricks will cause condensation, black mould and potentially rotted floor beams. Rockwool will not help in this situation. You can cut wall the insulation board to a loose fit between the beams and use spray foam to fill the gaps all around. The radiator upstand pipes can be replaced with Hep2O allowing a neat connection without solder. Use an inline stop valve to isolate the pipe under the floor. When the system is depressurised you can make one cut and lose virtually no water. Use a block style cutter and have the valve ready to quickly push on. Keep a wet vac handy to clean up spills but you probably wont need it.

You need to use the thermostat vale stop cap. If you simply screw it to zero there's always the risk a bout of cold will open the valve.

Hi Ali, good to see you are back. Nice job, neat and tidy. What software did you use to draw your plans?

Any update on how this has worked? I thought it was best practice to take up the flooring and have the insulated board go all the way down to the top of the ceiling below, you have left a big gap under the floor board area so would be nice to know what its been like 1 year down the road... Cheers

Good video. How did you prevent moisture migrating and condensing around the wooden beams? I'm doing a similar job but I'm afraid that the wood in the walls will rot because of this excessive moisture.

Hi,just wondering how your getting on with the insulated plasterboard,if you’ve had any issues and if it made a difference with keeping your house warm?

Could you stick on acoustic boards using the foam and would it work to deaden the sound more than drywall adhesive or fixings? Possibly 2 layers of acoustic plasterboard?

Good tip with emptying the rad. Just a note re cavity insulation from the 80 ( and 90 and even into the early 00s) only a lawyer of about 50 mm would likely have been added, still leaving a 50mm cavity which can still be filled to greatly improved the overall insulation. The cavity insulation would originally have been installed by the block/brick layers and could often have been poorly done as they would have been working around wall ties which caused gaps. The insulation would also have been low density polystyrene.

Great vid. Really helpful!.How thick is the line of foam when installing it to the wall?. 10mm?

I've read that moisture can travel from outside inwards through the wall. Is this something you considered? I think there are special coatings that can be painted on to the exterior which will stop water getting in but allow moisture to escape. Thanks for the video :)

How did the corners hold up to cracking where you've used the flexible sealant? I'm going to get my walls skimmed and the plasterer is recommending scrimming the corners.

A good trick to not create a visible butt joint if you can’t fit a full board in a space, instead of fully cutting in half you can score the back side and snap the plasterboard, leaving the front paper intact. Works well with normal plasterboard, maybe some sealant in the back where the cut was in this one could work

Thanks for your video, I'm interested in doing this to improve my epc, do you know of it as simple as install and having an inspector round to mark up

Great video, how does the room feel now for warmth? Any issues with the fixings?

Hi just one thing you should do is around the window , leave the slab over hang beyond the reveals ,then later trim the foam only from the back with a craft knife , cut your slab infill around the window and foam in place when all is dry cut off excess slab around window giving you a slab to slab corner , hope you can follow , important to avoid cold bridge at window reveals 👍

If you had removed the plaster board on the front wall would that have saved you a significant thickness? Thank you for a superb and very clear description.

Could you tell me what about damp moisture membrane / you did closed air pockets via using foam as square on plasterboard I think personally you should put foam horizontal to plasterboard however due to high moisture density in air after few years it could create damp in between plasterboard and wall. I have done this using silka mulitpor is not cheap however no possible to create damp as you actually extended natural wall breathing

Great video, just what im looking to do. Question? Isn't a dryliner track required with solid walls?

Next time you remove a radiator,after screwing down the thermostatic valve fit a blank to the outlet because they have a frost stat in the valve and they can open up if it gets cold and flood the room.

Great video. Thanks! Will this solution work for a loft conversion where there’s one side wall which is party wall to next doors loft (unconverted)?

Well done. 👍

Good video, our house is a 1934 property with solid brick walls. We had a external wall where the hallway/stair is. The plaster had blown and wall was sweating as you could feel it and almost smell it. We removed all plaster back to brick and allowed the wall to breathe and dry out. After a few month we got to work but only had a depth of 35mmish to use where no suitable insulated board product would suffice. After some research we applied a tanking slurry, a render mix and floated finishing plaster on top. Wall is dry as a bone now and no longer that cold to touch wall... but videos and knowledge is needed on the subject as there is so much conflicting info!

Do you have a video of adding insulated board to a bay window? Mine has ancient expanded poly tiles over the insides of the solid stone window mullions. This looks terrible and the joints/gaps encourage mould. However Im not sure how to mitre the boards to fit?

Can I use this insulated plaster board & form to seal for my garage wall ? Garage wall made single wall ( 2 side ) & other side made up with block Will that helps ?

Curious that you described Phelonic Core as better insulator than PIR. I had a look and the thermal conductivity seem almost exactly the same. Curious what is really the difference.

Nice job you can always put a washer before hammering in the mechanical fixing

Hi. Would you say foil backed plasterbourd be sufficient for the same use. I.e external inside wall?

I love learning from your vids Ali.. Just curious as to how far a can of adhesive goes for this type of work as they aren't cheap. Can you remember how many you used for this job pal?

I'd like to do this in my bathroom and apply over existing plaster which has been painted. Would it be best to remove the existing paint before installing the thermal plasterboard?

I agree with the fact that there are a lot of cowboys on the market just wanting to scavenge on government subsidies for insulating your house. A thorough bit of research is needed and will pay off if you're going to hire someone to do the job for you. I'm planning to have my exterior walls insulated from the outside and rendered, this is a real specialist job and I chose to go with a builder which already has 20+ years of experience with the process and offers 20 years of guarantee on his work! So worth the extra bit of money. The other companies which were invited to make an offer trough one of these websites were you can get 5 offers didn't even reply back, so they probably considered the job as too complicated for them because of some technical details of the house. Another advantage of the chosen builder is that he can do some structural changes on supporting walls at the same time, so it isn't necessary to have two different companies having to work in each way or at different times. But as for the easier jobs, I agree on the fact that getting the government subsidy does not cover the added cost for labour when outsourcing, as one of the requirements is that the job must be done by a certified company, so you're still saving money when doing it yourself without getting the subsidy.

Hi Ali, thanks for a great video. Can I ask, if you are getting a new EPC certificate for this house, do they check if it's done by a certified installer or do they accept DIY jobs and presume it's installed as per product manual? Thanks

Such a super helpful video thank you! I've just done the same in our living room following some of your instructions. Just wondered though and I've already done the same as you but now I'm second guessing myself, would the capping off of the insulation with plasterboard at the window reveals be a point at which vapour could pass behind? I'm hoping I don't need to rip off the plasterboard I've fixed here! 😂

Does foam adhesive reduce air cavities behind the insulation board and thereby reduce amount of condensation/mould?

Hi Ali. I'm looking to do this in the next few months. Can I hide a gas pipe in the insulation,by cutting a channel out the back of a panel. Great video. 👍

Hello, Great video. Is it not necessary to bring it back to brick when doing this job? I’m going to undertake this in my sons room

Great video, i done this throughout the house all external walls last year using kingspan plasterboard sheets. I Would recommend soudal plasterboard adhesive, great stuff, then big twist headed helical fixings.

what if you just paint the brick with some like acrylic paint so there is a liquid barrier? Paint is thin. or even paint the brick with clear epoxy?

Hi mate , how much does the foam expand ? Do you get a tight fit

Does the plaster go on fine over the joints were u applied the acoustic sealant

Can I tile this board when fixed this way? Would it hold the weight of the tiles in a bathroom? Thanks

Good job. Any thermal bridging since installation? They say don't stick stuff to external walls..!?

Do you think this method would be good for the ceiling?

How do you find it now any issues?. I'm worried there wouldn't be enough ventilation behind to allow the brick to dry out ?

I was advised by my council to fit tantalised timber on the wall first and 72.5 insulated plasterboard, what's your take on that?

Good job. Is there still some risk of condensation on the solid wall even with the foil backing vapour layer and sealant? Also how many cans of Insta Stik covered how many boards?

10:15 Question, you mention a continuous line of foam. Could I ask what the thinking behind that is? I was once told to only do vertical lines, so any moisture that could be in the brick and would condense between brick and insulation - can trickle down the wall. Would it be better to trap air in there, or to create a cavity of sorts?

Hi there, i know you posted this 2 years ago wondering if you can offer some advice. How is it holding up and have you had any issues with this type of technique? ie condensation or mould forming? Lastly has it helped make the room a bit warmer?

Brilliant videos Ali been watching since the garden building. I am about to embark on the insulated plasterboard and will be follwing your guidance. Can I just ask what the purpose of the 15mm gap is at the bottom that you later fill with expandable ? Thanks keep up the vids

Hi, I am looking to do the same thing in a garden Annexe which I am now using as a home office. My issue is that the walls have been previously finished with a very rough plaster finish. What are your thoughts on this? e.g. would I need to re-plaster to ensure a flat surface prior to installing the boards? Although this approach does seem fairly double handed. Great video, I had considered all the same options you had and this definitely helped me to make my decision! Thanks a bunch! James

Hi i like the video however its a myth externally insulated buildings dont suffer with this problem. Consider the scenario. Cold house, You return home on a cold day and put the heating on. You increase the temp & humidity in the home but the thermal mass of the wall is slow to respond and lags behind the room temp. The moisture enters the fabric due to higher humidity internally compared to outside and as the thermal mass mass of the wall is slow to respond Dewpoint occurs instantly on the inside of the wall. Moisture migrates through the fabric and becomes trapped behind the external insulation.. Bad bad bad bad. Only mitigation against this is a mechanical ventilation unit to combat the humidity rise. Internally insulated walls respond quickly with the rapid temperature change and do not lag behind the internal temp. Most insulations used for this have low permeability and and moisture going beyond the insulation is minimal. Also with the external structure not wrapped in external insulation, the building will eventually permeate the moisture to atmosphere instead of being trapped. This is why timber frame buildings use an internal vcl eg polythene and external vapour control layer which allows moist to escape to atmosphere . The other way around would be a total distater. Spent 13 yrs testing /investigating building defects, air leakage testing. Cavity filled and externally wrapped solid wall buildings are something that keeps cropping up...

i noticed you lift a litttle gap at the bottom and sealed. could i leave a bigger gap if i wanted to. say about 100mm.

Warning, if there's a chance that the room temperature will drop below, I think, 5C just closing down the TRV is not enough as they open at about this temperature as a built in anti-frost setting. Use a proper screw on valve depressor thingy, they usually come with the TRV. Been there done that, didn't enjoy the soaked floor experience! Secondly, I think the insulation on all these insulated boards acts as a vapour barrier.

Great videos you are making, so after 2 years how is it going with the walls?

Yes

From my experience i would not use dob n dab on foil faced pir foam backed plasterboard as the adhesion between the foil face and the dob n dab mixture may seem sufficient initially i have found that it will separate after a short period of time.

Any opinions would be appreciated on my idea thanks, if it will work? As solid walls need to breathe. I thought of why not use good Quality roofing membrane (Foil will sweat with vapour) on the solid brick wall which is breathable and acts as a water vapour barrier on the wall then batten up and use rockwool (insulated and breathable) Inbetween then use moisture plasterboard used for bathrooms? No condensation inside + warm wall and breathable brick wall. Good / Bad ?

Great stuff. Would this method work with foil backed panels (e.g celotex pl400)? Thanks

Hi, great video and thanks for sharing this information, very helpful, I'm about to start doing the same to my house, the wall is solid stone built, I took off the old black ash plaster as it was loose and left with just stone, I was was going clean up as much dust, a thin layer of PVA and then dot and dab or foam now after this video, would you think this would work? Cheers

What adhesive to use for sticking PIR to Plasterboard?