Polyurethane Form Insulation a good idea?

diymonkey

Hi everyone,

I've got a call today from a company coming down to survey my property for cavity-wall insulation.

They do Polyurethane Form (Technitherm) Insulation. My property is a semi-detached house. The bottom-half is yorkshire stone and the top-half is pebbledash, so I assume the wall under the pebbledash is bricks? It's classed as a "Hard-To-Treat" wall.

Anyway, I've read a lot of horror stories that it's not supposed to be safe to get cavity-wall insulation done as it would mean a chance of rain penetrating through, causing damp, condensation, mould, etc.

I know it's short notice, but can anyone experienced please advise whether it's worth having this done or not? Is it too risky? Would it cause problems?

Also, how can I check this company is safe and leggit to carry out this job?

Lastly, if something went wrong and the company was not willing to rectify it, what channels would I have to go through?

Thank you.

MX5huggy

I've had it for 3 years now and are happy. It's not like any other insulation if installed correctly it's impervious to water. Unlike mineral wool or polystyrene beads (the 2 common insulation products) it cannot be removed by vacuuming it out. It's a better insulator than the others it's significantly more expensive. Read the BBA certificate for the product. I actually had BASF Walltite installed so look at that. It leaked inside in places during installation move stuff away of wall particularly around junctions.

diymonkey

MX5huggy wrote: »

I've had it for 3 years now and are happy. It's not like any other insulation if installed correctly it's impervious to water. Unlike mineral wool or polystyrene beads (the 2 common insulation products) it cannot be removed by vacuuming it out. It's a better insulator than the others it's significantly more expensive. Read the BBA certificate for the product. I actually had BASF Walltite installed so look at that. It leaked inside in places during installation move stuff away of wall particularly around junctions.

Many thanks MX5huggy. Just a bit anxious as I don't want any condensation or damp problems later. I have a few more questions:-


1. In the event of a serious problem, such as developing of damp or the company unwilling to investigate or fix any condensation issues, who do I turn to and what are my rights?

2. There are websites that say this foam is a) difficult to extract & b) breaks down over a period of time. How difficult is it to extract this and what's the procedure?

3. What's the difference between BASF Walltite and Isothane's Technitherm? Which one is better?

4. Do you/Did you have any condensation problems?

MX5huggy

Your rights I probably limited to taking legal action against the installer. It's not something I considered much the traditional insulation products are supposed to be insured by CGIA but when you look into it getting them to do anything is like pulling teeth, same with NHBC on a newish build.

It's stuck to both internal faces of the cavity, like something stuck to a blanket, to get it all out you'ed have to demolish the outer skin of mechanically remove it then rebuild the house. Not really worth considering.

Condensation has improved, I don't get mold on the walls anymore because the dew point of the walls has been raised. Adding more heat or ventilation could have done the same. Websites talking about foam insulation are often talking about Urea-formaldehyde foam insulation which is an old nasty product that degrades.

I can't see any significant difference between the products.

diymonkey

Well it's very worrying if it's very difficult to take action against a negligent company if CIGA or NHBC won't help. I thought it was BBA that dealt with these issues though?

It's even more worrying to hear that it would be virtually impossible to take out foam if there was an issue. Again this is surprising....I mean what if a surveyor makes a mistake and doesn't spot that there is a corroded wall tie, which in turn causes damp? Would that mean the person would just have to live with it? Surely not?

What sort of condensation did you have before the CWI? Was it just on windows or was it on walls too? How much of a difference has it made?

To be honest, we have a lot of condensation on our double-glaze windows, so I hope it doesn't get worse with this.

FreeBear

diymonkey wrote: »

My property is a semi-detached house. The bottom-half is yorkshire stone and the top-half is pebbledash, so I assume the wall under the pebbledash is bricks? It's classed as a "Hard-To-Treat" wall.

I also have a semi, lower half is brick, and the upper half is pebbledash (horrible stuff). The upper half is solid brick, so no cavity to insulate so I would need to add insulation externally or loose a bit of wall space and do it internally.

The give-away to solid walls is the width of the windowsills - If upstairs are narrower than the ones downstairs, the cavities will not extend the full height of the building. If so, don't get conned in to paying semidetached house prices for what is in effect a bungalow install.

MX5huggy

BBA test the performance and approve installation methods of products they don't provide any warranty.

Interesting you mention wall ties, it's other functionality is to do the job of wall ties if they are failing. Any damp would have a primary source such as failed render , pointing or DPC.

The walls used to grow mold , they weren't really wet but mold would grow. Now it doesn't. I still get condensation on Windows (maybe more) but these are now the coldest surface so it is expected, I don't have trickle vents. Or extract fans in bathroom or kitchen fitting any of these would improve it.

malc_b

The reason for a cavity in the first place is that the inside of house has a high moisture level compared to outside. The amount of water air can contain is relative to air temperature which is why is call RH (Relative Humidity). 100% is saturated air. Typically it will be 40-60% inside at 20C. 55% at 20C is 100% when that same air falls to around 13C. That's why you get condensation on windows etc. The air next to the window is cooled to 13C or lower by the cold glass.

Air also passes through walls. The amount will depend on the wall construction. Old style solid plaster is pretty air tight. Plasterboard on dot and dab often leaks like a sieve. Air passing from the house into the cavity hits the cold outside wall and condenses. Water runs down the outside face to ground and away. The idea of beads or blown fibre cavity fill is to allow that condensing and draining to continue. The worry with a solid fill is that voids or later settling cracks will allow the condensing water to track back to the inside walls.

diymonkey

@ Freebear - I've checked the wall thickness and it's approx 16-18 inches for both upstairs and downstairs, so not sure what this means

@ MX5 - At my place we mainly get condensation on the windows, but it can be quiet a lot, hence my concern and so many questions. I spoke to BBA & BUFCA this morning and they've both advised that this company is approved installer. However they weren't willing/not able to discuss my primary worry of warranty and whether it would cause or exasperate any issues.

@ malc_b - Thanks for the explanation. What do you suggest for my type of property?

thebaldwindowfitter

FreeBear wrote: »

The give-away to solid walls is the width of the windowsills - If upstairs are narrower than the ones downstairs, the cavities will not extend the full height of the building. If so, don't get conned in to paying semidetached house prices for what is in effect a bungalow install.

Not always true sometimes windows are fitted inside the cavity meaning a narrower window board inside

Mx5 is right about the foam it is like what they fit to hot water cylinders and is solid we did a patio for somebody and had to remove brickwork below a window hell of a job . water will get through it though .Condensation in your home is not caused by insulation it is caused by heating and ventilation patterns

bluesnake

Not though about insulating the outside walls, as it could be cheaper, and avoids less volatile chemicals off gasing. Could be better insulation too, just look up the airgap with and compare it to the isulation and thickness of the outer cladding. just google R values to find how effective materials are per inch thickness

If it goes wrong as in the youtube vid where in the USA where someone ceiling was badly done, they had to rip the whole roof off the house to make it habitable again, which you can't really do in the uk with no walls and live in a caravan for a year in your gaeden.