So I want to redo the insulation on my house this year and I don't know which way to go. Do I just use the old school pink stuff, the denim batts, spray foam, the organic spray foam, rigid panels, spray in loose fill?

There are so many choices now and I just don't know which way to go. I am going to strip off all the interior dry wall (on exterior walls) and redo it. I don't want to tear off exterior cladding, so any option that involves that is out.

What should I be considering and what is the best choice for my home and the environment?

If you are stripping down to the studs, I would say that the way to go is with expanding foam insulation. It will give you the best seal, the highest r-value and no gaps in insulation. How old is the house? I ask because if you have a much older home, you may not have a moisture barrier (Tyvek type product or building wrap) and the spray foam could help you in this respect.

I know there are some drawbacks to foam on the waste end, but there may be some biodegradeable choices out there now. I haven't looked myself.

Spray foam is definitely the way to go if you are going down to the studs. I can't say enough good stuff about spray foam. I wouldn't advise being there for the installation unless you have one of those jump suits because the stuff is pretty sticky and you don't want to be breathing it in... Lungs, liquid, expanding, solidifying. I think you get the point. Its safe though, and there are more and more non-toxic versions and even the biologically based ones too. I have seen the denim batts but for my two cents, they still fall short of spray foam because time will only cause them to sag and leave gaps.

spray foam seems bad for the environment. do they also release CFCs?

Spray foam doesn't use CFCs. At least I haven't seen a product that does. They use a pump to spray a two part solution into a cavity and that two part system chemically reacts and expands. The reason that you see installers wearing masks and protection is that the product can be dangerous to the touch and extremely dangerous if you breath it in and it hardens in your lungs.

are there any alternatives that you would suggest?

Alternatives to what? Spray foam is one of the highest performing insulations on the market. If you go with a closed cell sprayed to fill all the stud bays and then trimmed back, you will get superior insulation and moisture control. Why do you need an alternative? The question about CFCs has been answered. There aren't any. Its not an aerosol application. Its a pressure spray applied mixture, where part A and part B meet only during application which causes the chem reaction/expansion.

In the UK spray foam is expensive so best to use Kingspan Insulation Slabs which also comply with Building Control regarding noise reduction. These slabs are so good that it is possible to convert a garage to living room without building inner leaf of bricks - great where space is an issue.

DavidTroy, spray foam is a little more expensive than batts or boards, but per R value its not that bad. Kingspan makes mostly rigid foam insulation products and while they seem good at first, over time, they degrade in performance up to 50% and you have to do proper installation to ensure that gaps are covered. The ideal super insulation application with rigid foam involves two staggered layers and is expensive as well. It is an easier installation in comparison to spray foam, but you lose benefits such as a moisture barrier.

We recommend to clients fitting wood burning stoves that they also fit cavity wall insulation. What happens is the concrete hearth generates heat through the sub-floor void under the floorboards. When this reaches the outer wall it is forced back into the void by the cavity wall insulation. Without this insulation heat generated through the hearth and under the floorboards disperses into the wall cavity. A third of the heat produced by the stove is lost in this way. Woodburning stoves are now DEFRA approved for "clean air" locations - the Morso Squirrel 1412 has a second chamber where woodsmoke is recycled before dispersing into the chimney saving 30% on fuel costs. Woodburners can also burn smokeless fuel but we recommend scavenging for wood. Logs need 8 months to dry out (inside) but worth the wait as the heat is fierce. Do not burn "green" wood which has not properly dried out as the tar produced can start a fire in the chimney - very expensive. Do not store logs on the hearth as it will void your insurance in the event of a fire. Store them in baskets either side of chimney breast. Do not confuse stoves with open fires where most of the heat goes up the chimney. Since fitting our own stove 2 years ago we have not used the central heating as it warms the whole house when you are properly insulated. ***URL removed by Administrator***

Hi Bob the Builder - Kingspan produce foil backed slabs with moisture barrier and can be fitted with foil insulation tape over gaps. They are easy to cut to size to fit between rafters to save headroom then insulated plasterboards can be fitted over the rafters. There are now cheaper alternatives approved by Building Control - Jewsons carry a line called Quintherm which is just as good. These slabs are also great for insulating floor voids - again where head height is an issue. We have converted garages to living room without needing inner leaf of bricks using these slabs in new timber floor, stud walls and ceilings. They are equivalent to 300mm of rockwool without losing a foot of head height.

DIY is always cheapest route. Buy your own rigid insulation boards. Kingspan used to have the monopoly but there are now cheaper alternatives - Quintherm is approved by Building Control. For walls buy 75mm foil backed insulation boards which can be cut to size to fit tight in between the studs- no need for moisture barrier - be sure to leave 25mm ventilation gap before you board over. For ceilings use same between the rafters again leaving 25mm vent gap. Then fit insulated plasterboards over the rafters. This will achieve the same U value as 300mm of standard loft insulation so you save 200mm headroom. For new timber floors suspend foil backed slabs between floor joists with either battens nailed to the joists or, because they are so light, just use nails. Unlike the spray foam, you can fit these boards over time - when you can afford them. You can wait for special offers or buy in bulk to save money and fit these boards in your own time. No worries about accidentally being exposed to this spray foam before it has properly dried out. This DIY option will save you a lot of money to spend on other green products - like a DEFRA approved wood burning stove which is far cheaper and more affective than central heating. If you are remodelling your home look at electric underfloor heating which is zoned, not fitted wall to wall, and very cheap to run. With a wood burning stove heating a room up to 45m2 and underfloor heating in kitchen and bathrooms you need only use the radiators in the bedroom. Electric heated floors and stoves are the energy saving heating devices of the future because you will never be ale to generate your own gas. By fitting solar panels, underfloor heating and through scavenging for wood for the stove, massive savings can be made on your annual fuel bill.

I could have sworn the topic was insulation and you go rambling on about stoves. I am not even going to address that as its way off topic. You are right that rigid insulation boards are cheaper when you are just looking to meet the standard R-values in homes, but when you go up to high performance or super insulated standards, you loose some of your cost savings as the bulk of the price is for the product while the bulk of the price for spray is in the specialized installation which doesn't go up as much for a thicker coat. You never addressed the issue that rigid boards lose R-value over the life of the product, which is not an issue for most spray foam insulation.

The moisture barrier from the foil coating is questionable at best and does not compare to the moisture control you get from closed cell spray foam. The gap control is also an issue. Unless you have perfectly straight studs (hahahahaha) you will have gaps and that tape you mention has NO insulation value, leaving a gap in your installation.

I get that rigid foam is a good DIY option and its cheaper to install but the fact is, over the life of the product and with all other aspects, you aren't saving that much money. Its not just about installation cost. Once we can get past the cost being defined as what you pay upfront, we will see that the easy option is rarely the cheapest.

HI Bob

You're right I did go a bit off piste - we are very passionate about cheap heating. We did get a quote for spray foam on a house where there was no roofing felt and you could see the stars. It seemed a good option as the foam actually adheres to the slates and will prevent slippage in bad weather. But the quote was in double figures and cost the same as a loft extension and new roof. Costs may have come down over the years so we might consider this again especially on old roof with slipping tiles. But we would have to be sure it met all the building regulations espectially Part F Ventilation and Part J adequate air for combustion appliances. This can be achieved with Cavity Wall Insulation which costs around £300 for average 3 bed semi. I still think if someone is replacing their own dry lining they can achieve the U cvalue demanded by building control by using rigid insulation slabs fitted over a separate foil moisture barrier if they wish. With the 25mm gap for ventilation and services (wiring) this will satisfy Parts E, F, J and L of Building Regulations. If expandable foam is used behind dry lining boards how would you get the wiring in for new electrical sockets in the future. And how would you vent the space and prevent damp from condensation. We have spent best part of the summer following cowboy insulation firms who have dragged rockwool insulation over the cavity wall but not fitted a venting strip. We have seen roof joists dripping wet and turning green because of this lack of ventilation. How do you vent wall and roof if this spray foam is used? And is it safe once it has set? I would love to learn more about this product especially if it costs less these days.

David, Where are you from. In some areas spray foam may not be an accepted insulation or meet the building regulations, but you seemingly are talking about very specific codes that may not be applicable to everyone. I guess what I am seeing is that you are arguing specifics while BTB is arguing generalities. Apples and oranges here.

I do know that to ventilate roofs with spray foam insulation, there are plastic channels that slide between the joists and then the spray foam is applied to the bottom surface. The issue that you mention with joits being dripping wet sounds like poor roofing system installation. There should be a moisture barrier outside of the sheathing and without that, the problem lies with the roofing and not the insulation.

Also when you look at the cost of any sustainable product, you have to look at more than installed cost. You have to life cycle cost. BTB is right though that rigid foam loses performance over time, and spray foam (especially closed cell) does not.

I might consider this spray foam if I found the perfect house and never wanted to move..But I would not want to make such an investment otherwise because buyers will not be willing to pay more money for this insulation. My local building inspector says the insulation slabs take many, many years to degrade. With the money saved you could invest in a woodburning stove and cut your heating bills for years to come. Buyers are willing to pay extra for this - especially if you save your energy bills over the years. Since I installed a woodburner two years ago I have not used the central heating radiators and have already made my money back.

Where I can see that this spray foam will be a good investment is in older houses where there is no slater's felt so every time there is a slipped tile the rain pours in. This spray foam will bind the tiles so no need for new roof. It would definitely be worth the money then.

I think you have your mind set and you are all about rigid foam insulation (maybe you even sell the stuff), and you are coming to the discussion with little to no knowledge of spray foam. I think you are just trying to push this single method and saying that anything else is worse.

A setup that is more efficient than the one you are presenting and emits FAR less CO2 would be a super insulate home (old or new) with two layers of rigid board on the exterior with staggered joints all sealed with tape and then a 3" layer of open cell spray foam on the interior of the stud bays (either sprayed into open bays or through a wall fill application. An upgrade to closed cell would be more expensive and not necessary. All windows would then need to updated to either double or triple pane, argon filled, low-e glass windows. All gaps and leaks would then be discovered through an application of a thermal camera, sealed and otherwise fixed. This would create an air-tight home. To ensure that the air remains clean and to avoid sick-house syndrome, an air exchange unit would be installed that also has a heat exchanger. Pulling in fresh air to a natural gas power heating system or even better a geothermal HVAC system with a small HVAC back-up unit.

Burning wood is not the solution. No matter how efficient you make these stoves, they still emit greenhouse gasses and still require the cutting down of trees. Those two facts make it certain that your solution is not scalable. What we need is scalable solutions. This may work for you.

I admit it - the only thing I know about spray foam is that it is expensive in the UK and not possible to do yourself.

As a HETAS qaulified engineer I DO know about woodburning stoves. Wood only releases the carbon monoxide it soaked up during its life when it is burned and is widely accepted as the most eco-friendly fuel for these stoves. You should only burn wood from sustainable sources and never burn wood with more than 20% moisture content. You should never burn treated wood as this will release toxins into the air. And never burn bits of MDF which contains formaldehyde (as a binding agent) which is harmless till it is burned and releases toxic gas. It is also used as a preservative in some paints so you should never burn painted wood either.

I find a mix of wood and smokeless fuel produce the best heat and less fuel is needed since we got cavity wall insulation which was pumped in through holes drilled in the exterior wall. It was noisy but clean and well worth a little bit of hassle. It is also subsidised by the energy suppliers here in the UK and costs less than £500 for a 3 bed semi

On the subject of double glazed windows I agree with you that these should be upgraded to E glass. It is not necessary to remove the whole unit but just the glass. I can fit 3 new glazing panels for less than it costs for one double glazed unit so people should not be put off upgrading their glass and keeping the original frames.

When buying a newbuild house always check the double glazed units - is there a lot of mastic in there around the frame? This will shrink with the plummeting temperatures we now get in the UK and you will have to fit cloaking strips so knock something off the sale price for this.

Older houses don't tend to have these problems as they are mostly fitted by local firms with regular inspections and compliance with Building Regulations. But newbuilds are not scrutinized by local building control. This is because each house comes with a 10 guarantee. But look at the small print - you are not covered for faulty maunufacture or fitting of the double glazing. You are only covered if the glazing starts to mist up. Because the glazing is so much cheaper it will probably fall within your excess and you still won't be able to claim. Best place for an NHBC certificate is on your woodburning stove.

If I inherited a newbuild house or won one as a prize it would be up for sale on the same day unless it was a self-build which has to be certified by local building control.

Saying that wood is the cleanest source for the stoves is missing the point though. Combustion in any form is a dirty process. Your poor reasoning that it only releases the carbon DIOXIDE (not monoxide) that it absorbed is a terrible argument. Burning oil, coal or natural gas only releases the stored carbon in the form of carbon dioxide as well (note that they don't store carbon dioxide but carbon - CO2 is released as a product of combustion when one carbon atom binds with 2 oxygen atoms). As efficient as you think wood burning is, its the opposite. The amount of energy that went into producing those trees, far far far far outweighs the heat that you can get from burning it.

Hey there

You are right trees only emit carbon dioxide - typing error by my Missis - but I was quoting from the HETAS training manual and wood is the best fuel for stoves and open fires for it takes far less to produce the heat we need here in the UK with our -10 and worse temperatures than burning smokeless briquettes. We are only making the energy companies rich by sticking to gas and electric although I do think the future is a combination of electric underfloor heating - which can now be sourced from a very small area and a multi-fuel stove burning properly seasoned wood from sustainable source. I am rejoicing in having a woodburner fitted because it has all but cured my dog of arthritis - the ambient heat has got into her bones and she is now on injections every 26 weeks instead of every 6 weeks. With planes going over my head every 5 minutes (exempt from 20% fuel tax we will have to pay from January) I feel less inclined to worry about the planet than my dog athough I faithfully recycle every bit of household waste and only use the car for work. Me, my missus and our two dogs have practically no carbon footprint at all and are entitled to a bit of comfort in the winter.

iIf you want to get on your high horse you should be lamenting the fact that we opened the trade gates to China and now we can never stop their onward enslaught on the planet. Some people think it is China's time, that we all enjoyed the industrial growth we achieved through burning coal...but that is the same as saying it is China's time to have slaves because we in the west once did..Developing countries do not have the right to slaves or anything else we have got wrong in the West.

In the current freezing temperatures and the existence of emerging China and India and the waste of energy that is Las Vegas I am afraid people here in the freezing UK feel that all their efforts are a bit pointless.

So they are entitled to do DIY insulation (which will not perish during their lifetime) and burn wood on their stove to keep their babies warm without worrying about the impact when the rest of the World could give a damn.

If you are from USA you should not be lecturing UK residents about their carbon outputs but should be lobbying Congress to stop the obscene waste of energy taking place in Vegas, Atlantic City etc. Why do you need so many ights anymore when they are well established tourst resorts. Why does you government not insist on only solar powered lights allowed - God knows you get enough sun.

Having had my say I still appreciate the fact you are expert in spray foam insulation which is so expensive in UK. Are there contractors outside of Uk in Europe who we can trust?

I would take the opportunity to pick your brains- my dream is to build an eco friendly house half submerged in a hill/cliff and built from straw bales. I cannot think of a better insulation product in this than spray foam. So my question is how do you spray foam insulate a straw baile house.

I am intrigued now about this spray foam and wonder whether there are other companies in Europe willing to travel to the UK for this work?

I am grateful to you for what I have already learned about this product and am getting more and more interested in it - if only it was not so expensive in the UK.

cheers
Dave