# External Insulation



## laoisfan (14 Jun 2011)

Hi

Just wondering if anyone has got any external insulation done?

See http://www.externalinsulation.ie

Our house consists of an old cottage ( ~70 year old, concrete ) and a dormer style extension ( ~30 years old ). It has peddle-dash finish all around.

Just wondering if anyone has got this and what their experience was like? Cost, final finish, how was winter ?

I plan on contacting some of the company listed on the above website to find out more details, get a quote etc.

Thanks in advance.


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## Lex Foutish (14 Jun 2011)

A number of my friends have gone the external insulation route and all are happy with it. It's much less hassle than going the insulated plasterboard route as you don't have to move rads, sockets, skirting boards, etc. It's much more expensive though, and I read on boards.ie that some companies increased their prices by around €4k when the grant of €4k was introduced.

Some experts reckon that external insulation is better suited to houses that are occupied all day long and that internal insulation is better if the occupants are out of the house during the day. That's because an externally insulated house takes longer to heat but will hold the heat for longer. The opposite is true of internal insulation.


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## onq (15 Jun 2011)

The expense in internal insulation is as Lex Foutish says.

However the expense in retrofitting external insulation can centre on -


 relocation of rainwater downpipes, waste soil and soild vent pipes, and gullys
 detailing at eaves
 detailing at rising walls and thresholds
 replacement of window sills for insulated metal sills
reduction in width of side passages
rehanging or replacing outward-opening windows and doors and/or their hinges to allow them avoid hitting the insulated return
installation of MVHR system or compromise the insulation by fitting sleeved vents.
There may be other stuff as well, but that should give you an idea of the complexity of it.
Its one of the main advantages of Cavity Fill insulation that neither Lex's concerns nor those listed above arise.
Of course designing from new avoids a lot of these things.

ONQ.


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## laoisfan (15 Jun 2011)

Thanks for the replies guys, some stuff to think of.

I will contact some the companies and see if it possible to get a quote ( sure no harm is getting them to come out to quote & ask some questions on the points you have raised ).

Cheers!


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## onq (15 Jun 2011)

Laoisfan, I suggest that you take a moment to look up articles on external insulation on the Construct Ireland website and elsewhere.
There are some cases studies there which will tell you what to inspect in relation to the "look" of the finished product and the methodology in construction.

=========================

One disadvantage internal insulation is that with a highly insulated surface to a room, it can lower the temperature so much on its cold side.
This can drop so low that condensation can occur behind the insulation and in front of the external wall, depending on the exposure of the wall and incident sunlight.
This can lead to smells and in extreme cases health problems, so its worth remember the old adage, you can have too much of a good thing and proper sealing of internal surfaces and penetration is important.

=========================

The main problem with cavity fill insulation is that its difficult to tell whether the fill has been complete unless you undertake thermal imaging of all the walls so filled.
If there are gaps then its a patch fill in cold spots, otherwise there is a possibility you may get condensation attracted to these cavities, relatively speaking.
Left within the wall this may eventually migrate out, but this cavity wall problem is effectively hidden - I haven't done much investigative work on it.
Just don't think its the "cure all" solution.

=========================

In fact no insulation method is without problems and the all need careful detailing and inspection on site to ensure that the careful detailing is correctly installed.

ONQ.


 [broken link removed]

            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.


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## serotoninsid (15 Jun 2011)

@laoisfan:  If you get quotes, maybe you could give an indication of rate/sq. m or yrd?

I've been monitoring this over the last couple of years - and I think they can do better..


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## Agnette (17 Jun 2011)

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.


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## onq (25 Jun 2011)

Agnette said:


> 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.

_*T*__*his 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.


 [broken link removed]

            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.


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