Loft insulation?

[Mogweed]

We're renovating a mid-terraced house that was built in 1874 and currently the only access into the loft is through a skylight over the stairs and it's quite dangerous. We need to get into the loft for the rewiring anyway so I'll probably cut another access hatch in one of the bedrooms instead.

I've not been in the loft for about 30 years so I really can't remember what it's like up there, but as all the ceilings in the rooms are 12ft high and it would be such an effort to get in there, I can't see it ever being used on a regular basis for storage, or anything else for that matter.

I know that there is no loft insulation up there but, given the fact that the ceilings are 12ft high [1] is it worth putting loft insulation in or will the 12ft high walls leach all the heat before it can escape through the ceiling into the loft anyway? And, I *do* know that there is 131-years-worth of soot, dust and muck up there. I suppose good practice would say to get rid of it but how? Can you hire hoovers capable of that task?

[1] Because of the size and position of the windows we can't lower the ceilings, or at least not without a lot of extra work and expense. The house was my mam's until she died a few months ago and we're doing it up with a view to renting it out. It needs to be rewired, replumbed, have central heating installed etc., etc., and the only money we have is what she left in the bank so whilst lowering the ceilings would reduce heating costs, it would take too much of our money to do.

Cheers,

Mogweed.

[tony sayer]

In article , Mogweed writes

If it were mine I'd leave the ceilings exactly as they are and just insulate the roof space. After all if you're not intent on living there then why go to all the bother of lowering the ceilings in case there is a bit extra to be saved. I'd look towards making something of the ceiling height!, seems fine to me.

While on the subject are there local authorities around who dish out grants (or incentives) for loft insulation on private rented accommodation?.....

[Owain]

Any insulation will help, and loft insulation is cheap and effective. As you are going up there anyway, it would be daft not to do it.

You can, but if you're rewiring, replumbing etc etc there'll be a lot of mess anyway. Putting loft insulation over the lath & plaster ceilings will help to keep the dust down.

If you were doing this in a 'habitable' house and not rewiring etc - just wanting for access to insulate - I would suggest a scaffold tower and opening a hole in the slates for access.

and probably not be cost-effective. Loft insulation, factory insulated hot water cylinder, and general draught-proofing of doors and windows will be most cost-effective. As you are putting in new CH anyway, worth putting in a reasonably efficient boiler (rather difficult not to under new Building Regs).

Owain's "property ladder" tip of the week - buy some nice seedlings now in "plug plant" form, pot them in yogurt pots on a sunny windowsill, and they will be ready to go into the garden later in the year when you are ready to market the property, and a lot cheaper than buying grown plants from the garden centre later.

Owain

[Mogweed]

Thanks for the reply Tony. I'm not sure about grants for loft insulation on private rented property but it's something we'll be looking in to - I'll repost when I find out.

Cheers,

Mogweed.

[Doctor Evil]

131-years-worth

Put in 12" of Rockwool insulation, which is not that expensive. Ceiling height doesn't matter regarding insulation.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account

[Geoffrey]

The house sounds very like my Mum's house. Same age and the loft hatch above the stairs - is it basically a 2up 2 down with kitchen stuck on the back?

Anyhow - I remember when we got the loft insulation put in and it made a significant difference - from the outside you could tell simply by the fact that the snow did not melt on Mum's roof but did on the uninsulated house next door. It IS worth doing.

If you don't intend to use the loft why clean it? Wear a mask :)

Don't even think about lowering the ceilings - you'll do damage to the value of the house.

We did the same thing to Mum's house when she went to live with my brother. Spent about £18,000 in all (that includes stuff like repointing, replastering, rewiring and all the other things that you need to do to a neglected Victorian house before you can rent it out). This is in London though - I expect it would be cheaper elsewhere.

The local estate agent reckoned we added about £50,000 to the value of the house...

[Andy Hall]

Given the age of the house, it presumably has solid walls. WIth the height involved, unless you lowered the ceilings and insulated immediately above them to create a cold area above, a considerable amount of heat will go through the walls.

It's certainly worth insulating the loft because that will be a considerable heatloss in a mid terraced house, but it is not worth using more than about 150-200mm of insulating material. The difference you would make would pale into insignificance compared with losses through the walls and through draughts.

Having high walls will tend to result in more temperature gradient from floor to ceiling as well. The implication of this will be that it will tend to take longer to warm the rooms from cold than with a place with lower ceilings.

When you come to work out the heating requirements, you should certainly use a proper heat loss calculation and not just guesstimate. It's probably then worth over-provisioning the radiators so that the place warms up quickly, but then to use thermostatic radiator valves to control output and hence costs.

If you were planning to live in the place, then you might consider some of the ideas that you suggested like lowering the ceilings, plus insulating walls, doing something with windows and so on. However, given the financial equation and renting out, there has to be a limit, and obviously there is cost associated with wiring and heating installation.

At least with this approach, the only tenant complaint might be heating costs, but then if you have insulated the loft and done the other things that you have suggested, I think that you will have done what could be reasonably expected, whether you are renting it out or eventually decide to sell it.

[Doctor Evil]

131-years-worth

Two wrongs make a right then. It is mid terraced with a small area of outside wall. Most wall area most probably will be party wall. It is best to make the ceiling air-tight by using silicon to block any holes and have an insulated and sealed trap door, and 12" of Rockwool. Irrespective of ceiling height heat will be lost through the ceiling at a rapid rate with a thin layer of Rockwool. Insulating a loft is easy and cheap.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account

[Mogweed]

Many thanks to all who replied and have given us lots of good info - it's much appreciated.

Cheers,

Mogweed.

[Anna Kettle]

They are now handing out grants to anyone who has no or minimal insulation. No means test

Anna

~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

01359 230642

[Lobster]

Don't know if this is the same as when I looked into it a few years ago, but AFAIK grants are given towards the cost of a contractor installing the stuff; even with a whopping discount on that, the outlay was still so much more than diy'ing that I didn't bother pursuing it further.

David

[Andy Hall]

No, I am simply pointing out that there is no point in going to extremes on loft insulation as opposed to a reasonable provisioning when in comparison large amounts of heat are going out through the walls.

We had this discussion before and I gave worked examples with numbers to illustrate that there was no point in going above 150mm or so. Yes there was a small amount to be gained, but it was a tiny fraction of the heat loss through the walls. Perhaps you have a short memory or like spending other people's money.

You don't know that the area of outside wall is small. For one thing the ceilings are very high in comparison to many properties so loss through them is greater in proportion.

It may or may not be. This doesn't alter the amount going out through the front and back walls which is likely to be an order of magnitude greater than that through the roof even if you were to only put 100mm of insulation there.

It would be if it were a more modern house. This property is over

150 years old and unless one were to implement modern insulation standards on it comprehensively, there is little or no value in going mad as you are suggesting on one aspect.

Nobody was suggesting using a thin layer. 150mm is a very adequate level of insulation in the context of this property. If we were talking about a modern house with cavity walls, cavity insulation and double glazing, then there is a marginal case for going to thicker insulation.

Insulation material is reasonably cheap but it isn't free. In this case 300mm is overkill.

The case you are making is equivalent to arguing for a 40W bulb rather than a 60W bulb when there is a 3kW fire in the room.

[Doctor Evil]

Lord Hall, 12" is not extreme. In fact, there is no such thing as extreme in insulation. Put is as much as you can, with 12" being the minimum.

It is terraced. At least half the walls is not outside wall.

..and you got it wrong then too.

With no idea of practical reality.

There was a lot to be gained in the bedrooms, as the ceiling forms a large part of the room surfaces. It also works the other way around. The 12" of loft insulation keeps the heat out of the bedrooms in summer.

In a bungalow the ceiling forms the largest surface area of the house. Think of the upstairs as a bungalow.

See above.

It ios not a detached house, that is for certain.

..in proportion to what?

You have an odd idea of how terraced houses are built.

Because more is going out through the outside wall the roof should neglected then. What logic.

Mad about what? Insulating the loft to 12" is hardly going mad. The house will be reasonably air-tight as two sides are not outsides walls. When replacing windows and doors obviously install sealed units to make the house more air-tight. The walls will not be cavity, so pretty well air tight there too. It is air leakages that cost in heating fuel. It is well worth having sealed doors and windows and ensuring the ceiling is air-tight too. Then the 12" of insulation will have a great effect.

So, in time new sealed windows would be installed. Having the sealed loft ceiling and 12" of insulation would compliment that and already be in place.

It isn't and thin in any property.

You really don't know do you.

Highly cost effective and it will pay for iteself very quickly as oil (fuel) prices rise in future. They NEVER go cdown.

What a mad analogy.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account

[Andy Hall]

I think that you've just demonstrated my point exactly.

You don't know that. Some mid terraced houses are narrow and deep, some are not. Some have substantial rear extensions which have large areas of outside wall. I once owned a house which was exactly like that.

Obviously in proportion to the losses from houses with lower ceilings and walls...........

Not really. I have owned a practical example where there were substantial areas of external wall due to a rear extension. This is a very typical construction if the property is not a two up/two down.

I didn't say that at all but simply highlighted looking at things in proportion. You have demonstrated that you are incapable of doing that, so there's no real point in discussing it.

Going over the top with one aspect while doing nothing about the rest. This is what the OP has said that he will do for cost reasons.

Obvious to who? Not everybody want to replace the character sash windows with plastic hermetically sealed ones. Window replacement wasn't on the agenda anyway

The losses through solid brick walls in comparison even with uninsulated cavity are huge. Have you ever looked at a table of U values? Do you know what they mean?

It is one of the reasons. Heating designs are based around an assumed number of air changes per hour. Not everybody wants to live in a sealed box as you seem to advocate.

IN comparison to the heat loss through the walls, the difference between 150 and 300mm of loft insulation is negligible.

Do I need to do the sums again to remind you?

Who said anything about even wanting to replace windows?

The problem for you is that I do and can easily demonstrate it.

On the contrary. It describes the situation that you are advocating perfectly.

[Tony Bryer]

Beyond a certain thickness of insulation the energy used to make and deliver it will exceed the amount of energy it ever saves.

[Anna Kettle]

The grants have improved a lot cos the government is putting money into energy saving now. Even got mentioned in the budget. The insulation still has to be installed by a contractor

Anna

~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

01359 230642

[Doctor Evil]

What tripe. Lord hall is saying that the heat loss is less because the ceiling is higher. Shishhhhh

Your proportion means that higher ceilings have less heat loss than lower ceilings. Another Lord Hallism.

The bedrooms when taken into isolation will greatly benefit, as the ceiling is a large cold surface.area.

Obvious to anyone who knows anything about housing.

Sealed character windows are available.

It is now.

Another Lord Hallism. Solid brick walls are notede for their airtightness. Cavity walls are noted for their air leakiness.

The point was air tightness. Air leakages play a large part in heat losses. Make a poor U value house air tight and the bills drop and comfort goes up. Put insulation in and the benefits even greater.

Yep.

Another Lord Hall assumption. As the Canadians say "Built Tight, Ventilate Right"

Nonsense, it will have great effect in those bedrooms.

Yeh, get the skule physics book out. The coloured bumper edition from under your pillow.

They will be replaced. Fact.

Lord Hall, you just don't know.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account

[Doctor Evil]

Over what time period? In time as oil prices rise, that means higher cost of insulation and home running costs, the payback time will be much shorter than you think. So, getting it in now makes lots of sense.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account

[Andy Hall]

Once again you demonstrate your misunderstanding of simple concepts of physics.

If a ceiling is higher, then the wall area is greater. If the wall area is greater, then the heat loss is greater. If the heat loss is greater, then more energy is needed to heat the room. If more energy is needed to heat the room, then more money has to come out of your piggy bank to pay for it and there is less to spend on sweets.

Is that clearer for you now?

It really isn't worth bothering to answer that. I am sure that everybody else understood.

As you know, or perhaps you don't, heat losses through surfaces are calculated using U values, surface area and temperature difference. Multiplication is involved in this. If it causes you difficulty, then you can buy a device calld a calculator to work it all out. These days they even work from the sun.

In order to calculate heat losses and costs you have to look at all the rooms and their expected temperatures, not take them in isolation.

That's what I thought.

It may be on your agenda. It wasn't for this thread.

This is one of your best for a long time.

We are talking about heat loss *through* surfaces.

A solid brick wall of two courses (228mm) has a U value of 2 W/m^2.K

A cavity wall of brick/cavity/block/plaster with no insulation has a U value of 0.75

THese are from official tables produced by the Building Research Establishment and represent a difference of 2.7:1 in heat loss.

The discussion was not about air tightness. It makes some difference but not as much as you imagine when ventilation is at the recommended rate.

We aren't in Canada and are not talking about anything close to their form of house construction. Making these comparisons is ridiculous.

I think we need to find your Janet and John Book of Sums....

Not within the scope of the current project.

[Doctor Evil]

Lord Hall you forgot that it is a nice thing to keep the heat in so more money is available for sweeties.

...you don't say...

The idea is to put insulation in not size a heating system. The bedrooms would greatly benefit by having 12" of insulation in the loft. (see above)

...you thought?

The point was air leakage. Please read back Lord Hall.

Air tightness is a part of it and you know nothing of it.

Do physics not apply over there?

More Lord Hallisms. Who said change this terraced house to a Canadian type of house?

It's under your bumper book.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account