Roof insulation

[STYRBJORN]

One point about about double glazing that you are not told is that it's the frames that cost serious money, the glass is cheap as chips. So if you try to do the decent thing and replace old wooden frames with uPVC on a one for one basis it costs a helluva lot more than having fewer, larger, windows.

Ric

[nightshade]

For ethical reasons my B in L chose wooden frames with double glazed panels,
so they are available

[SheffieldLass]

Originally Posted by nightshade

Don't forget to Check For Bats in the rush to save money

And they might be roosting in the wall cavity. I think that is where the ones in my house are, over the winter .... I'm monitoring the droppings over the year to work out their habitation pattern. They seem to go through the roofspace, not roost within it - it is just the droppings that are the give away. Either that or they've just returned, and it is a casual spring and autumn roost. If they are in the cavity that would certainly quash any plan for installing cavity wall insulation ...

[cara pace]

Originally Posted by nightshade

Don't forget to Check For Bats in the rush to save money

And over the coming months, please check for swifts too.

[brendaward]

We have had cavity wall insulation put in, mineral wool. Done by the Gas board at a Subsidised price. When we had to make a hole in the wall for a new pipe we discovered it was no more than a cobweb. Useless!

Years ago we had another property done with foam and that stopped any damp penetrating and was as warm as toast. I understand that foam is no longer used unless in sheet form because of the chemical content being released into the building. Remembering that we was advised to keep good airflow after foam installation years ago for at least one week.

Chemicals aside the foam was far superior to the mineral wool.

As far as the long term effect on the environment goes it is foolhardy to not give all buildings the best insulation possible to cut down our usage of power.

Buildings that were not designed with cavity walls can be insulated from the inside, tanking with space blanket, lathes and plasterboard. At present this tanking is rarely done. It can save a fortune on heating and save on energy use.

Unfortunately the contractors who install these things are not very knowledgeable and where bats are concerned ignore droppings. Surveyors only popping heads into loft cavity and not doing proper inspections. Our on doing just that. Fortunately we do not have a roost although bats have lived there at some historical point.

Upvc windows are a damp barrier in their properties but wooden windows could draw in damp if no effective barrier is between them and a cavity wall that has been filled.

My advice is if you have anything done don't just leave it to the contractor, do some investigation and research yourself. Then keep an eye on the work.

[Cowgirl]

I've observed that big sheds (factory/warehouse type) are often insulated on the inside with that spray on foam stuff. Is that the same stuff that can't be used in cavities except with sheets Brenda.

My works office suffered a load of burst pipes (time off yippee!) this winter, even though it had proper loft insulation & lagged pipes. However my thinking was that if the actual inside of the roof had been sprayed with this stuff we may not have had the problems. Loft insulation stopped the heat escaping from the office, ok fine, but it effectively meant that the temperature of the loft was not much lower than the outside temp & at -15, even lagged pipes couldn't help! Does my theory hold out?

Do new offices/houses take this sort of thing into account?

[brendaward]

Don't think it was the same stuff as it took a good week years ago for the foam to solidify and chemicals to evaporate through the walls. The Brown orange substance in roofs sets on oxidation so I presume it is a different kind of chemical. I think with all of the foams they are safe when set.

Tanks in roofs are very vulnerable because they have an overflow pipe to the outside that is permanently open for safety. Unfortunately when very severe weather hits this freezes the inside temperature of the tank and can cause pipes to freeze if they have not been used for a time.

The tanks and pipes should still be lagged as well as the roof to stop them from becoming too cold. They are often neglected as that will do when lofts are insulated. After long cold spells many businesses get in trouble with freezing, because they have left an unheated building with no water flow. The lack of water flow being the biggest problem, one which is not easily resolved.

[bigdave60dog]

Originally Posted by Grapler

Where adding insulation to your house is a great idea, especially if you dont have any, there are some things that these companies forget to mention.
Firstly and very importantly is the addition of insulation over existing electrical cables. The resistance in the cables creates a certain amount of heat and unless your house is only a few years old you should have the wiring checked before you install or top up the levels of insulation. The other big thing is cavity wall insulation.This type of insulation can end up being an absolute nightmare. Generally if your cavity is clear with nothing sitting on the wall ties then it is an excellent way of conserving heat but if you have dirty wall ties you are looking at damp penetration into your house which will cost you money rather than save it. The place that we all forget about is the floor. Insulating the floor can be more effective than double glazing. A couple of inches of ridgid insulation is enough to keep your feet warm. Lastly, and my pet hate, is double glazing. Double glazing is a brilliant idea but where it falls down is the amount of hype given to it by the salesmen. You can achieve the same "U" value (how they measure heat transferrance) by putting up a heavy set of curtains. They sell you uPVC windows that they say are maintenance free, which they are not, and fail to tell you about how dangerous they can be in a fire.They fail to tell you how much damage they do to the environment in the production of the plastic and that it takes a few lifetimes to degrade when it eventually ends up in the local landfill.

Dont take this the wrong way, I am not against saving energy or money for that matter all I am trying to say is take a look at the big picture before you make a decision and ask questions. Being a Building Surveyor with a special interest in building conservation, we are listening too much to the hype and spin from salesmen and politicians. I have experienced some real disasters in the past few years mainly because people do not know the right questions to ask.

Seems sensible advice to me. The only thing that I would add is beware of using polystyrene insulation round cables without sheathing. It can cause it to melt or catch fire.
I do like double glazing though, Quiet and convenient even if you do need to live a thousand years to recoup the cost in energy saved.
And I hate installing glass fibre loft insulation. One of the worst jobs in the world.
Dave

[bigdave60dog]

Surveyors hate spray on foam on the inside of anything wooden especially rooves. It prevents the free flow of air thus rendering the wood vulnerable to fungus attacks. This is especially true of Tile and slate rooves where this stuff is often advertised as being an ideal insulation.
Sorry if you have already got this on your tile roof. There is a straightforward remedy that does not involve the removal of your roof. It is a bit complicated for this forum but any good roofer or surveyor will put you right.
Dave

[ForestPaul]

Originally Posted by bigdave60dog

And I hate installing glass fibre loft insulation. One of the worst jobs in the world.

We used sheep wool when we did ours, processed into felt bats and treated with borax, very easy to handle. We also used it to provide sound proofing and fire separation in the ceiling of the main downstairs room, sticking it between the joists from below, then putting new plaster board up. Something that would have been highly unpleasant, if not impossible, using glass wool.