New roof

btedds

I am having my roof re-done and am trying to work out how much it should cost. I have been quoted between 25-50k!

The house is 350m sq and I am having the roof off, raised by one brick course to make enough room for insulation and then all put back on again with added insulation.

Quotes so far are between 25-50k.

The quote are for, removing existing tiles, felt etc- then laying celotx between existing rafters above existing ceilings, batten, counter batten and refit existing tiles on thinsulex. Oh and redoing all the lead work.

I have a sloped celing and so I can't insulate my roof in any attic space (as there isn't any) and all the roofing contracors I have managed to come out (which is only 3) have all said the roof has to be raised and then re-roofed to fit the insulation required.

I have no idea if what they are saying is correct or what the price should be -any help gratefully received!

dougk_2

Why is the question I would have!
If its needs a re-roof have that done, but i can't say it would be cost effective to hhave the insulation done. Sureley you could remove the exsiting ceilings and have them replaces with insulated plasterboard?

btedds

I have been advised that it needs doing to meet current building regs - is this wrong.

Also have a lot of beams on display on and it would mean cutting insulation board to fit between them, in my living room alone that would mean 24 separate pieces of insulating board being fitted. Basically my ceilings look like chess boards with all the beams.

Would it still be cheaper despite this?

Any opinions would be really gratefully received - as I do feel like I am being taken for a ride with this one!

dougk_2

It is a part of the building regs, you are correct.
There is exemption that says that the cost of insulation cannot be repaid via energy savings over a 15 year period.
I would guess that the cost of basically what is removing the roof and adding a course of bricks before replacing it would cost more than you would save.
Even if they do raise it by one layer you will still loose the "feature" of the beams - because from what you are describing they would cover them over with insulation and plasterboard. I wouldn't like this. I'd rather keep the "checkerboard approach".

There needs to be an airgap between the top of the insulation and the roof membrane (or felt). I believe this needs to be aleast 50mm. if the beams are say 125mm + deep then its possible to insulate between them. The insulation shees are easily cut and wouldn't take to long to install. Its something you *could* do yourself to cut down on costs (say in the evenings) while they are doing the roof, as long as the contractor is happy with this.

General info can be found here:
http://www.planningportal.gov.uk/england/genpub/en/1115315235321.html

and here:
http://www.northdown.gov.uk/uploads/docs/alterations%20to%20roofs%20floors%20and%20walls.pdf

btedds

Great advise. I did not know about the exemption, you are right - it would never pay for itself! So does that mean we would just have to get as much insulation in as is cost effective?

They are quoting to leave the internal ceilings as they are and insulate between the rafters from the outside (is that what you were suggesting I could do myself in the evenings?) - so far no-one has actually been under our tiles to see how deep the joists are, so I am not sure how they know that the roof needs raising!

I would guess that they don't think my rafters are 125mm deep!

If I can use the exemption, could I get away with less celotex (ie. if the gap that already exists is under 125mm) and not have to raise the roof. I think they are only raising the roof to get the 75mm celotex in and to leave the 50mm air gap before the membrane?

Again thanks, dougk for all your help!

MX5huggy

I am confused, what are you having done? Just the roof or some big refurbishment.

There is no requirement to meet current regs for like for like replacement.

I think you need some independent advice, Architect, Architectural Technologist or a Surveyor.

will-he-payitoff

Could you not use the space blanket type insulation?

dougk_2

MX5huggy wrote: »

I am confused, what are you having done? Just the roof or some big refurbishment.

There is no requirement to meet current regs for like for like replacement.

Actually there is!

To quote local authority information:

From 30th November 2006 there are significant changes to the Building Regulations
that cover the Conservation of Fuel and Power in buildings. As a result of the
changes, works that may have been previously exempt or not covered by the
Building Regulations are now controlled.
As a consequence you are required to submit a Building Regulations application for such works.
The regulations have now been extended to cover repairs, alterations, replacement and renovation
of what are called the buildings ‘Thermal Elements’. This applies to both domestic and
commercial buildings.
Where you intend to renovate or the replace a thermal element - you are required to carry out cost
effective insulation improvements. The new building regulations, Technical Booklets F1 and F2,
provide guidance on what are considered cost-effective insulation upgrades and replacements.
You must also carry out a condensation risk assessment of the effects of carrying out the
improvement works and take suitable precautions to prevent condensation damage.
EXAMPLES OF WORK REQUIRING THE SUBMISSION OF A BUILDING REGULATION
APPLICATION:
• Renewal of pitched or flat roof coverings – e.g. re-tiling, re-slating of pitched roofs or re-felting of
flat roofs.
• Renewal or replacement of ceilings under a roof space or flat roof (with or without the renewal of
the supporting structure).
• Renewal of a finish or cladding to an external wall area or elevation (render or other cladding) or
applying a finish or cladding for the first time.
• Renewal of internal wall finishes to an external wall (excluding decoration) or where you are
applying a finishes for the first time e.g. re-plastering or dry lining of walls.
• Renovation or replacement of a solid or suspended floor, involving the replacement of screed or a
timber floor deck.
• Renewal of cladding to external walls or dormer cheeks.

btedds

OK, so how about I look at this from another angle?

If my rafters are not 125mm deep (ie. I cannot get 75mm celotex and 50mm air gap) as suggested by roofing quotes and I don't want to raise the roof by one brick course and spend 25-50k doing so?
I am pretty sure that all of the membrane needs replacing as I can see daylight in the small amount of roof I can actually get to without taking the tiles off! And the lead-work all needs re-doing!

I now have to meet current building regs as kindly pointed out by dougk (but only if cost effective).

I think I would be silly not to put some form of insulation in there if the roof has to come off to replace the membrane, but what would be the best way to proceed?

And how much should I be looking at for a replacement membrane and replacement lead-work on a roof of approx 350m sq?

knowloads

what about roof coating..... teeHee
I would certainly look at internal even if its onlt 1" THICK its would cost a hell of a lot less to do this and re-decorate. 25-50k is one heck of a difference eh??? You could even fit sealy false beams to get the look back.

Spendless_Dosh

You seem to be suggesting that in order to install insulation you will completely dis-assemble the roof, lay an extra course of brick around the property and then re-install the roof structure.

Is there a reason behind this?

Why not simply strip the covering off (including underlay and batten) install rigid insulation over the existing rafters and then counterbatten, underlay, batten and cover. (if you use rebated insulation board it won't raise the roof by more than 75mm (assuming 25mm counterbatten).

Any reputable insulation provider will be able to recommend a suitable board.