I too am considering external insulation. I live in a semi detached house with kitchen extension to the rear (the room most requiring insulation). The front elevation is half brick, half dash with bay windows. I am reluctant to apply external insulation to the front because of aesthetics and internally because of loss of space within bays. Would it still be advantagous externally insulating back and side walls? Any advise will be appreciated.
Hi Agnette.
Any insulation is better than none and a projecting extension that is poorly insulated has over six times the surface area of the removed walling to lose heat through.
Think of the your head projects from your body - air can get at it from all sides - this is why we lose most heat through our heads.
While I accept your pros and cons you'd better make a list to help you priorities things and make a decision, otherwise you'll never get any insulation in place before the winter.
Insulating the back and side wall will help, but insulating the attic will do more than these on an elemental basis.
Replacing your windows with hi-performance units will work wonders for any house, but the whole building needs to be looked at not just the insulation.
Therefore, you also need to consider this non-exhaustive list.
1. Installing an MVHR system
and sealing the house properly, including chimneys and air vents.
Do not do one thing and not the other - sealing a house and not installing an MVHR system including a suitable ventilation strategy to maintain air quality could kill someone. You also need to design the system so that it doesn't compromised fire safety within the dwelling or promote sound transmission between rooms.
2. Insulating the attic space, while installing a vapour check below the ceiling
and maintaining ventilation and keeping services, pipes and water tank warm.
Do not do one thing and not the other - super-insulating an attic will reduce temperatures in it during winter months and increase the chance of condensation internally. Consider following the line of the roof with teh insulation and ventilating the structure taking account of the requirements of both Part F and Part L of the Building Regulations..
3. Insulating the whole envelope to avoid cold bridging, including insulating walls, closing vents [see 1. above] and installing windows.
4. Install double door porch arrangements front and rear. This can involve a simple glazed porch to the front, and a route from the kitchen through the utility to the rear or side. This simple expedient, together with sealed chimneys, will help avoid the blow-through effect which happens when both front and back doors are open at the same time.
This argues against a piecemeal insulating strategy because any moisture in the air will find the coldest spot and your guiding intention should be to avoid large temperature drops in one location along the outer walls and roof.
This also argues against a less-than-comprehensive strategy for detailing, because the gables and eaves of the roof and the heads, jambs, sills and thresholds of opes all have to be correctly detailed to avoid those pesky cold bridges.
My best advice to you is to invite an architect around to look at the house, then
develop a comprehensive strategy for your home.
One thing you need to watch our for if insulating internally is to how to continue the insulation past / through the floor zone at first floor.
You also need consider how to avoid having a relatively cold ground floor, either by continuing insulation down to your foundation, insulating the ground floor directly, or some other method.
The reason I advise that you should involve a competent professional is because unless the work is done well and well-thought-through you could end up spending a lot for very little.
Please read my and other posters posts both here and in other threads on this matter.
Also have a read of the
Construct Ireland website.
On the matter of costs, I was talking to a main contractor the other day who recently completed an extension and claims that both insulation and glazing prices have gone up something like 20% on last year. If anyone could confirm and/or deny it would be useful to me and others who frequent AAM.
ONQ.
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All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.