Roof insulation

[Paul mabbott]

It's so easy to insulate roofs you wonder why more people don't do it themselves: reduces heat pollution and saves money ....
Snow retention is a good indicator of how well lofts are insulated:


If I were a salesman I'd go round taking pictures of peoples' roofs at the moment and then point out how much energy/money they're wasting ...

[SheffieldLass]

Given the grants available right now it is also very cheap to get companies to put it in. Although some won't do a top up of you have more than 100mm in already. Sheffield City Council are currently putting in insulation free in certain areas of the city. They recently did Walkley, now doing Norfolk Park. I nearly did not apply as I had 150mm to 200mm, and the companies that were always phoning me did not top up if you had that level. But Sheffield City Council did. So my old house now has the 270mm. Well, 320mm in places, (shhhh don't tell them) so very cosy.

Quite a few of my neighbours houses had no insulation in at all because there were no hatches into the roof spaces. And they did not take up the offer because they did not want to put hatches in. And other people do not increase the insulation as they have boarded out their lofts and they are full of storage. If you use lofts for storage it is quite complicated getting the full depth of insulation and have boarding and not create a condensation problem on the underside of the boards.

My new house needs roof insulation, only has 100mm but I'm having to wait for the electrician and plumber to do their work up their first.

[Billy Wobble Dagger]

We made the most of the deals that Homebase and B&Q had during September and October with the BOGOF deals. So are new house now has plenty of loft insulation. Just need to get the windows done next

BWD

[pitre]

Some of the energy companies are also in on the act. De[ending on your age 65+ a lot of loft and wall insulation is available for free.
Had our walls done but they ran out of funds to top up the roof

[BloomingMarvellous]

On my way home from a shopping trip tonight I noticed Alot of houses without adequate Loft Insulation.

[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.

[tufftie]

Originally Posted by pitre

Some of the energy companies are also in on the act. De[ending on your age 65+ a lot of loft and wall insulation is available for free.
Had our walls done but they ran out of funds to top up the roof

They always run out of funds towards the end of the year (autumn for some things) but they will start funding again soon i imagine (used to sell insulation for my sins!). They also do it free if you are on certain benefits

[Paul mabbott]

Originally Posted by Grapler

.......... 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.

Yes, there are (or should be) warning about this on the wrapping. I consulted my electrician and he assured me that it was okay for our circuit and, indeed, most domestic roofspace wiring. It would only be a problem in heavily wired industrial or commercial situations.
But certainly worth keeping in mind!

[SheffieldLass]

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. . ..

Absolutely correct.

Originally Posted by Grapler

... 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. ...

Absolutely correct.

I'm at the moment pondering cavity wall insulation, and as an architect am aware, maybe too aware, of the pitfalls. My house has a dense, pretty much impermeable render, except for cracks on the daywork joints, which will keep opening up due to thermal movement. Render is taken down to ground level. There are no weep holes. So water getting behind the render is likely to penetrate through to the brickwork outerleaf, but with the cavity at the moment seems to just run harmlessly down the cavity and it does not appear to reach the inner leaf, as no damp patches. There is no way I'd put mineral wool insulation cavity fill in, because, given the construction, that is almost bound to get saturated. And not only does that risk making the inner leaf wet but it would also suck more heat out from the inside of the building, making it colder and requiring more heating than without any insulation. And speed up wall tie corrosion, which will probably happen, in due course, as the house was built in 1950, so does not stainless steel wall-ties. I'd only consider the polystyrene balls as at least they don't absorb water. But having searched the internet for grants on those, they are very hard to find as they are more expensive than blown mineral wool, and take twice the time to install. Another issue is the speed at which they usually install the cavity insulation, they don't take the time to make sure it is properly filled (indeed it is difficult to get it properly filled even if done with diligence). Areas where it is missing, such as under cills etc will then be much colder and become condensation magnets. My neighbour (other half of the semi) has just had theirs done with mineral wool ... the cavity is nearly 75mm wide. So I'll see what problems occur with theirs. They are not living in the house yet, so it is not getting the normal occupancy patterns, heating plus cooking, baths etc, so it may it may not behave in the same way as a normally occupied house though.

Originally Posted by Grapler

... 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.

Correct again. I used to have timber sliding sash windows in my old house. Draughty, but the house did not suffer condensation problems at all, inspite of being solid brick. I used blinds at the windows, plus heavy lined curtains. I had discovered when I had my bed under two enormous, draughty sash windows in an earlier house, that the combination of a blind plus curtains made a huge difference in eliminating draughts and keeping in the heat, compared with the curtains alone.

My current house had UPVC windows and doors fitted 2 years ago (before I bought it). So good u-value levels to the glazing. Only the windows were installed without trickle vents. And the airbricks in the rooms had been removed a few years previously. Condensation is a big issue now. I'm looking to re-install some trickle ventilation. There was a case recently of a couple who could not get back into their house .. after two hours trying they ended up having to get the door opened with a battering ram. The condensation had frozen the door solidly to the frame. A new problem ... and one I've noticed is happening to my doors in my house. I've not needed the battering ram yet. The lock that penetrates the door without any thermal break runs with condensation - perfect example of thermal bridging and how it attracts the condensation.

In addition I notice my house has no ventialtion in the roof-space, and it has the old fashioned non-breathable roofing felt under the tiles. There has not been a problem up till now, but insulation in the roofspace is minimal (I'm about to increase it to current standards), but it was until very recently heated buy open fires, and had leaky windows. So I'll be monitoring very carefully the roofspace to see whether it now needs ventilation. Very easy to do in this case as it has a gable wall, so airbricks can be put in. So something else to be aware of if you increase your roof insulation and make your house more air-tight, your roof space/roof timbers may now become affected by condensation, and you may need to increase roof ventilation.

Originally Posted by Grapler

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.

Ditto, except I'm an architect interested in building conservation, not a surveyor ...

Melanie

[Digit]

One other point Grapler, and I speak from experience. Being over 65 at the time my loft was insulated for me, in so doing they pushed the insulation into the eaves, the result?
Buckets, literally, of condensation. Unless the ceilings have a vapour barrier the roof space must be ventilated.

Roy.