SEA Forum

A useful tip which I picked up and used recently:
I have been using cans of expanding foam to seal joints between insulation and walls, ceilings and floors. Recently I was told about foam guns. The £20 I paid for the gun has saved me £20 of wasted foam doing just one room, AND saved hours of time. The only supplier I have found is Screwfix. I couldn't find the gun on their website, but second try ringing the nearest shop I got an employee who understood what I wanted and confirmed that they had them in stock.

A foam gun is a rigid steel gun which allows you to use one hand to control exactly the delivery of foam. This saves a lot of time, skill and wasted foam. It takes a foam can which is the same as an ordinary one except that it has a large plastic screw thread to attach it to the gun. Once the can is screwed onto the gun you immediately pull the trigger to fill the gun with foam until it starts to come out of the gun nozzle. Thereafter keep the can on the gun until it is empty. the foam will not set inside the gun as it needs atmospheric moisture to set (that is why it does not set inside the can, the only risk point being the valve). So the gun becomes an extension of the can, and using it is much much easier as being rigid you can hold it in one hand, AND there is an adjustable limiter on the trigger to stop you foaming too fast, so you save time and foam. Foam waste and time are further reduced because the trigger operates a rod which operates a valve at the END of the nozzle , so there is minimal cleaning of the nozzle as it is protected from atmospheric moisture. Just scrape any bits of cured foam off the end of the nozzle if any has cured overnight. So once the can is on the gun and the gun full of foam, just pick it up,use it and put it down each time you need foam. NO CLEANING AT ANY TIME!

P.S. I have opened this subject, IWI (internal wall insulation) for any and all questions on the subject.

And another tip, this one from Nick Parsons. Insulated plasterboard sheets are made with the plasterboard just slightly larger than the insulation, so it overhangs very slightly. This is not necessary aesthetically as the plasterboard will be skimmed or the joint will be filled, but thermally it is bad as it creates a gap around each insulation sheet. So what Nick does is he cuts a sliver off the plasterboard, so that the insulation just overhangs the plasterboard, giving the tightest possible fit between the insulation of adjoining boards or walls etc. The gap between adjoining plasterboard is then filled later when skimming or joint taping.

Talking about insulated plasterboard I use expanding foam to fill between the bottom and the floor where the joint is covered by the skirting and not plastered. Other joints are usually plastered giving a vapour barrier, but if there are any gaps these can be foamed first.
Mostly I use separate rigid insulation attached to the wall and then covered by separate plasterboard. I leave deliberate 10mm gaps all around the insulation and foam into it before attaching the plasterboard. Joints between insulation boards can be foamed or taped with aluminium tape.

This is a product we used to insulate our solid walls last year. Still cost us almost £500 to do a 3 bed semi but much cheaper than the alternatives. I can fully reccomend however, it was very easy to apply and had finished the whole house in 1 weekend and the difference with the recent cold has been amazing. http://heatandenergy.services.officelive.com/6.aspx

Cambellt. Whilst I don't mind the advertising if you have received good service I think it is responsible to point out the there are an awful lot of these companies about. I would always recommend that people get a number of quotes from a number of different installers. Also just because a firm advertises that they are a member of a certain trade association or have received certain accreditations it is always best to check.
The area of insulation (internal, external, cavity, loft etc) is a minefield and many of the experts don't agree on the one best practise technique so my advice is to find an installer you are happy with, investigate with them which product will be best for your specific situation, think about how you will avoid thermal bridging and then get alternative quotes for exactly the same thing.

Good luck.

Gabby fully agree with your comments hence why I tend to put so much value on forums like these, referral is often the best advice.

We were very careful about who we choose as a friend had experienced what I think amounts to the thermal bridging you mention. If I am correct he had cavity wall insulation installed. His is a yorkshire stone semi, (rough cut on the external side hence does not provide a uniform cavity). This created a void which in turn caused damp on the internal wall! Not sure how he rectified it?

We chose Heat and Energy as they had infact measured for the job and advised our friends against having it done, though another firm had said they could not forsee any problems!

Campbelt

I assume that the product you have used is Sempatap. This is olny 10 mm thick and it appears, from their data, to reduce the U value of a solid brick wall from 2 to 1.58. This is not a very dramatic reduction when you consider the the building regulations require new walls to have a U value of 0.3. I assume that your main consideration was cost and being able to do the work yourselves.

I have internally insulated my external walls with Gyproc Themarline Super 60 mm. This was not cheap at about £50 per 2.4x1.2 panel and getting the surface skimmed, but I have achieved a U value of 0.35 and had similar disruption.

I would like people's opinion on the wonder Tri Iso insulation which is meant to, in only 7mm thickness, provide the same insulation as 200 mm of fiblre glass.

Tri iso insulation is highly suspect. see http://www.sustainability.ie/insulation.html . The releevant passage reads:
Then in July 2005, the Building Research Establishment (BRE) in the UK investigated two buildings in Scotland which had been fitted with Tri Iso Super 9, the predecessor to Super 10. The results of the study² indicated that the thermal resistance of the Super 9 was about 1.71 m²K/W. Actis had claimed a figure almost three times asgreat. The research carried out by BRE was funded by the ODPM (Office of the Deputy Prime Minister).

The BRE findings have some serious implications. Anyone assuming that a building insulated with Tri-Iso Super 10 (or other similar product) will be compliant with building regulations is likely to be disappointed. The architects who specify such products and the building engineers who sign off houses insulated with them may be leaving themselves open to litigation from clients who will understandably be very angry that their new home is not insulated to the required standard.

Far from asking questions, many builders are recommending Super 10 or its contemporaries to clients and are delighted to have found a product that is so quick and convenient to install………

I also use a foam gun, but bought it on eBay (new) for £11. The foam cans are also cheaper on eBay (£40 for 10 cans, incl postage)

Martin, is your Screwfix gun still good?, because I now intend to buy one, and although there seems to be many on the market, I will buy from Screwfix, I like the idea of the shut off valve at the front end of the gun
regards odbob