[shark]

What's not to like...

http://www.moneysavingexpert.com/utilities/free-cavity-loft-insulation

[mr__j5]

We actually got phoned up by the energy company offering us this.

They were rather stunned when we told them that we didn't have cavity walls or a loft space to insulate.

[slackline]

Its a bit of pain if you already use your loft for storage.

We were told it would have to be empty as they just came and laid a load of loft insulation down.

I'd then have to put in additional beams and relay chip-board flooring on the top.  As I'd already added additional insulation to the areas which aren't covered by chip-board flooring I told them not to bother as they were unwilling to give me the loft insulation to lay myself.

[SA Chris]

How are the gift horse's teeth anyway Slackers?

[slackline]

They could do with a scrape and polish.

When they came round offering to do it I'd actually forked out five months earlier for the additional insulation that I'd already laid and they had the intention of putting more on that which would have been almost two feet of insulation.

I also had no inclination to empty my loft of the crap I keep stored there as it would have taken a good day to get it down, then the hassle of re-laying the floor.  Fuck that shit, I'd rather go climbing.

If they'd offered the polystrene blocks the fit in-between rafters I'd have had some of those, but hey they're not that expensive for me to buy and I can afford them and there are others in society who might not be so well off who would benefit from free insulation.

[Stubbs]

The guys that did ours said a lot of people had turned it down because they thought it was a scam of some sort because they didn't believe you could actually get something for free!

[Andy B]

We've been offered this, but I've heard/ read that cavity wall insulation can cause damp (presumably due to it stopping air circulation?). Does anyone have any better knowledge on this.

[tomtom]

The real issue for my house - and for many others I suspect are solid walls.

Solid wall insulation is pretty expensive, and either means having cladding covered by render on the outside, or losing 10cm or so on the inside of each wall.. But - it makes a real difference. When I had the kitchen done (usual dog leg extension out the back in a terrace) I got the main outside wall insulated (battens on inside, layer of foam and insulating plasterboard on top). This has made a huge difference... shame the bedroom and bathroom above are baltic!

There are schemes to subsidise solid wall insulation, but its something that requires quite a bit of disruption - and lots of re-decoration if you go inside..

[SA Chris]

We did a bit of research before getting it done and apparently the damp is only an issue in areas that have "regular driving rain" there is actually a mpa somewhere that shows areas that get it (we don't apparently; at least we do get it, but not regularly). We got it done about 3 years ago and had no damp problems. Does make a lot of difference to heating' heats up fast and takes a lot longer to get cold.

There's a map here, probably better elswhere if you google (and yes I realise it's part of a website trying to sell you something, but the map I originally saw is pretty much identical)

http://www.wethertex.co.uk/driving-rain-damp-walls/

We are just out of the zone, and as we have no north facing wall (semi detatched) and the west facing wall is solid stone and small (ground floor only) we weren't concerned. However it looks like Sheffield is in the zone, so further research might be a good idea.

[tomtom]

Problem is, I have a nice yellow brick fronted double bay terrace house - that I dont want covered with Pink render (or white for that matter).. Though I wouldnt mind getting the back done...

How much was it?

[SA Chris]

With all the subsidies and having a pregnant and hormonal woman give them hell down the phone when they missed the first installation date ( ) We ended up paying £80.

http://www.wethertex.co.uk/driving-rain-damp-walls/

We offer a clear “invisible” water sealant designed for home-owners who wish to keep the natural look of their brick or stone walls.

[tomtom]

Thats sealant, not insulation! - which involves 5-8cm of fibre/foam, battens then rendered cover sheets... You wont be seeing any brick through that!

[Wipey Why]

I've got someone coming round to see if they can give us some free insulation. Our house is 1920s build, so it may or may not have cavity walls. (As a surveyor I should really check myself, but they are going to come around and tell me anyway so why bother)

Has anyone had any problems or stories in respect of the free insulation.

[SamT]

Problems with damp are fairly rare now - they use blown fibre, rather than foam or beads, which has been treated I think to make it water resistant (I picked some out of a bucket of water that was left outside and filled with rain - the water ran off like water off a ducks back).  Had our 1920's house done a few years ago.  Top job.

You can tell if you have solid walls by looking for a course of headers on the outside i.e. the ends of the brick.  If you can see a row of those - or various ones dotted about (english cross or flemish bond) - they are solid.

The thickness is also a give away - if you have 9 inch walls (plus a bit for plaster) they'll be solid.  If they are more like 12inch - it'll have a cavity.

[burbistan]

The beads - variously branded but e.g. Springvale's EcoBead Platinum - are great, waterproof, cannot form damp bridges and do not settle/compact. They really work - my rural, detached and exposed (Peak District) house has a 75mm wall cavity and I had them put in 2 years ago: the difference is amazing. Sadly I didn't keep super detailed before and after data but we definitely run the house a degree or a degree and a half warmer, and we definitely use half the LPG we did before. Even taking the degree-days into account (two cold winters before the beads went in, mild winters after) I think we are using two thirds of what we would in an equivalent winter before beads - and we are warmer.

Miller Pattison and North West Insulations do them among other places.

I have no links with either of them (used NWI for our installation) and I would recommend watching them or any other firm like a hawk - e.g. check out how full the van is when it arrives and leaves so you know what volume went in, then divide by cavity width to work  out whether total area of your walls got done...

Aaargh - this is getting Too Long... I work in the energy conservation field, on the technical side, at a place that advises the public on insulation matters all the time, and I'm obsessed with it...

[moose]

Its a bit of pain if you already use your loft for storage.
We were told it would have to be empty as they just came and laid a load of loft insulation down.

One thing to ensure is that they ventilate the backs of any recessed spotlights you have in the ceiling below.  Badness ensues if halogen lights or their transformers overheat under a blanket of insulation.

[SamT]

very true moose - especially in plastic panelled bathroom ceilings - "whats that burning smell??) 

However - you'll probably find its not worth the bother insulating your ceilings if you have 6 or 8 little holes drilled in your ceiling that are then vented straight into your attic.  imagine you're in an air bell, with 6 little holes in the roof of it letting the air out the top - your going to get wet feet pretty fast.  Whats more - is you have a little heater (bulb) in the void, driving the air up through the hole. 
 

best getting light fittings that that hang below the ceiling (tracks, pendants etc) so the heat given off by the bulbs can be deemed useful heat and not lost straight into the atmosphere.

[moose]

The fixtures do a pretty good job of sealing the ceiling holes.  I would have thought heat loss from the room below would be negligible compared to the saving from the other 99% of the ceiling being better insulated (and upper floor lights aren't generally on long enough to worry about the best use of their heat output). 

As you say, the main problem is the fire risk, if a transformer gets hot there's a risk that insulation degradation will cause an electrical fault and fire (or that the heat build up will directly ignite any nearby detritus). 

[Jim]

We've been offered this, but I've heard/ read that cavity wall insulation can cause damp (presumably due to it stopping air circulation?). Does anyone have any better knowledge on this.

It basically varies house to house. Victorian houses were designed to breathe, hence the open cavity wall. When you fill it full of insulation you bridge the cavity so if the outside wall gets wet, it transfers through to the inside and you get damp.
Now really this shouldn't be a problem as the outside walls shouldn't become saturated enough for the water to come through, however there are many factors which can influence this, eg, state and position of things like gutters, DPC, drains etc... etc...
I have done a bit of research on this myself and decided to not bother with cavity wall insulation for now as it seems its not an exact science and can be a bit hit and miss.
I do think however that the chances are that if you have everything like you gutters, drains, DPC etc.. in order then you shouldn't have any problem

[chris j]

The beads - variously branded but e.g. Springvale's EcoBead Platinum - are great, waterproof, cannot form damp bridges and do not settle/compact.

We had graphite coated beads put in our 1930s walls two years ago. Supposedly the graphite helps stop water transfer or somesuch. We had the boiler changed at much the same time so it's not possible to do a direct comparison but with the central heating set a little higher than before we are using half the gas. Hopefully now the roof's being insulated to a decent depth as part of the loft conversion (rather than the 5cm depth of 30 year old stuff we had before) we'll see another good drop in usage...

But back to the cavity wall - we've seen no damp patches in the walls, the only thing we became aware of was that the extractor fan duct in the kitchen wasn't properly sealed as we got a slight trickle of beads appearing in a corner of the kitchen. Once I slapped some duck tape round it no more problem.

[SamT]

The fixtures do a pretty good job of sealing the ceiling holes.

yes - but there is clear airflow round the bulb and straight out the back of the fitting, so its essentially a hole drilled in your ceiling.

I would have thought heat loss from the room below would be negligible compared to the saving from the other 99% of the ceiling being better insulated

Without laying my hands on some firm scientific evidence, I beg to differ. Your comparing heat loss though conduction vs heat loss via air leakage.

I'm fairly certain that the heat lost via air leakage is much greater than the heat lost via conduction (if you have a leaky house).  Therefore having small vents drilled in your ceiling that let any warm air convected from your radiator (ha ha) straight out into your attic makes your efforts at insulation on the ceiling redundant.

Anyhow - its all a bit pot kettle, I have two 'eyeball' fittings in the bedroom, inherited from the previous owner, which I'm dying to get rid of.

I have done a bit of research on this myself and decided to not bother with cavity wall insulation for now as it seems its not an exact science and can be a bit hit and miss.
I do think however that the chances are that if you have everything like you gutters, drains, DPC etc.. in order then you shouldn't have any problem

There is a vast amount of research out there that point to the fact that insulating your cavity walls is going to save you a shed load of cash in fuel bills and make your house warmer.  I'm my travels I've never heard of anyone actually having had damp caused by cavity insulation.  Given the huge amount of properties being done, I'd have thought you'd hear of more actual cases.  Its all hear say, a hang over from the early days and experiments with it  - expanding foams etc.

Most damp in houses these days is caused by poor ventilation due to improvements in draught exclusion (UPVC frames - chimneys blocked up - etc.)  coupled with poor extract regime for cooking/drying laundry/showering etc.

MVHR is of course the answer to all these woes.

[robertostallioni]

do my mirrored ceilings not reflect heat/make further insulation redundant?

[SA Chris]

Does the heat you generate not make central heating redundant anyway?

[tomtom]

Don't you need to keep the the atmosphere chilled so things are suitably 'perky'?

[robertostallioni]

Nah, butter/jelly adhere to PVC/chainmail if its too cool.

[Andy B]

Most damp in houses these days is caused by poor ventilation due to improvements in draught exclusion (UPVC frames - chimneys blocked up - etc.)  coupled with poor extract regime for cooking/drying laundry/showering etc.

Shirley this is exactly what cavity insulation does? I was lead to believe that damp issues with this were based in the exacerbation of existing damp problems, by stopping the wicking and drying effect of air flow over areas of damp, rather than by the insulation creating damp bridges?

[Jim]

I have done a bit of research on this myself and decided to not bother with cavity wall insulation for now as it seems its not an exact science and can be a bit hit and miss.
I do think however that the chances are that if you have everything like you gutters, drains, DPC etc.. in order then you shouldn't have any problem

There is a vast amount of research out there that point to the fact that insulating your cavity walls is going to save you a shed load of cash in fuel bills and make your house warmer. 

I don't think anyone is doubting the fact that cavity wall insulation saves you money

[SamT]

Shirley this is exactly what cavity insulation does? I was lead to believe that damp issues with this were based in the exacerbation of existing damp problems, by stopping the wicking and drying effect of air flow over areas of damp, rather than by the insulation creating damp bridges?

two different types of damp innit.

Penetrating damp - rain hits wall - soaks through brick, bridges cavity, soaks though inner leaf and plaster, damp wall, wall paper falls off.

Condensate damp - you boil pasta for twenty minutes whilst having a shower just before you hang the washing on the radiator then make yourself a brew.  Litres of Steam/water vapour hang around thinking where shall I go cause you forgot to turn the bathroom extract on and your cooker hood is one of those recycling ones rather than a direct extract.  It finds a nice cold wall bit of wall cause you aint got no cavity insulation and forms condensation = damp wall, black spot mould and your wall paper falls off. 
Its gotta go somewhere.  (single glazed windows are actually quite a good 'sink' for water vapour if your looking on the bright side).

plus Rising damp - actually quite rare due to most houses having damp proof courses, where the damp is sucked up your wall leafs from the ground.

I'd say, off the top of my head + a bit that i've read online  + a chat with a couple of damp proof course sales men,  that condensate damp is by far the biggest problem.  I know that its an issue in our house and I'm looking into various MVHR extract options.

Its a minefield.