Advice/ opinions on external wall insulation

alex_163163

Hi all,
Just looking for any advice/ opinions on external wall insulation.
We’ve discovered since we bought it that the bungalow is a type of non-standard construction. We knew from the survey we had done when buying that the roof contained metal/ steel beams, not wood ones. But this wasn’t flagged in the survey as unusual or a problem.
What we now know is that our bungalow is steel framed, with brick outer walls (single skin). Then on the inside of that is the steel frame, and then on the very internal surface is insulated plasterboard. (I’ve learned that steel framed construction is usually more associated with concrete/ pre-fab type buildings but I’m 100% sure that ours is not.)
Due to this type of construction it is not suitable for cavity wall insulation, so I’m looking into alternatives as I find the bungalow chilly. I’ve been reading that external wall insulation and render is suitable for insulating older, Victorian era single skin houses, so wondering if any one on here thinks this would be suitable for our bungalow, given above info? It is technically a single brick skin walled building.
Are there any typically associated problems with external insulation that I should be aware of?
Any advice greatly received whilst I start research into this.
Thanks!

Slinky

I was suggesting this to my OH for the house we will be moving into in a couple of years time. He's not keen as he says it will mean the windows look funny, being set back further into your now deeper walls.

Mistral001

Have you considered getting the insides of the walls insulated? This would mean fixing timber studs on the inside with insulation placed between the studs and covered with plasterboard. It would mean extensive redecoration, but should not affect the external appearance of the house.

alex_163163

I had read about that but we have already redecorated a number of rooms before we realised/ understood the type of construction. So internal work isn!!!8217;t really something I want to do.
I!!!8217;m not bothered about affecting the current external appearance as I hate it (think stone clad but looks more Mediterranean villa - awful!). Some other bungalows on the street have been rendered and look lovely so on that respect I am all for the EWI system.
Was just wondering if there are any watch outs like with CWI - damp etc? Or if there have been installation problems, or hasn!!!8217;t really helped to reduce heat loss.
I am starting to do my own research but find this forum useful for extra snippets on info!

Furts

There has been a multitude of issues all over the country with EWI - it is the new CWI is this respect. From damp, to cracked renders, to insulation coming away, to bad reveals, to blocked roof ventilation, to countless issues. However, consumers will have heard little of this because lots of problems are on social housing and council housing.

CWI problems ultimately come back to consumers not being savvy and getting professionals involved. Some of those consumers working in the rented sector have been commissioning EWI schemes without professional help. Hence EWI has become a minefield.

Grenfell Towers was a reflection on all this. This was EWI as a typical example. Here was flammable insulation on the exterior of a building - who was specifying, who was inspecting, what management regime...? For you to ask if there have been any "associated problems"leaves me amazed - surely you follow the news?

That you have purchased a property not knowing the construction, not knowing the pitfalls, and not knowing about heating and ventilating it leaves me equally amazed. I also wonder about re-sale and ability to raise a mortgage, but here we are going off topic.

Sticking with EWI it is vital you seek professional help before going ahead, plus inspection of the ongoing work. I suggest you also seek insurance backed guarantees.

Be very, very careful with EWI. Good luck!

malc_b

External wall insulation should be better than internal. What you have to think about with insulation is where is the cold surface. Take the standard cavity wall construction. Moisture leaks through the internal plaster, internal brickwork into cavity, hits outer brick which is cold and condense on that face. That's ok as it just runs away. When the cavity is filled the materials are designed to let the water run down, not across. Adding internal insulation has to be done with care as it you add too much internally then the internal brickwork can become the cold stop where moisture condenses. Basically internal insulation moves the condense position inwards.

Adding external insulation makes the cavity warmer and so moves the condense line outwards. That sounds better for you as it moves the condense point away from your steel frame.

Furts

What year was the bungalow built?

Owain_Moneysaver

I think you need advice from a surveyor specialising in your type of building construction. In particular if your house type is classed as Defective there are approved methods of correcting the defect to make the house mortgageable and habitable. This might require a second brick leaf and cavity to provide additional structural strength as well as improving the thermal qualities.

I'm staggered that any competent surveyour couldn't recognise non-standard consruction when he saw it.

Furts

Owain_Moneysaver wrote: »

I think you need advice from a surveyor specialising in your type of building construction. In particular if your house type is classed as Defective there are approved methods of correcting the defect to make the house mortgageable and habitable. This might require a second brick leaf and cavity to provide additional structural strength as well as improving the thermal qualities.

I'm staggered that any competent surveyour couldn't recognise non-standard consruction when he saw it.

It may not be this simple. OP has said "insulated plasterboard" for the inner skin. This is a relatively recent innovation. So if OP has this correct the home could be a British Steel home from say the 1990s. If so, it is debatable if this would get flagged up.

However whilst OP clearly does not like what I have posted, a glaring fact remains. OP knew they were viewing an unconventional home when the survey spotted the steel roof members. To not ask questions, to not commission a thorough survey, to not do due diligence almost beggars belief.

System

It doesn't sound like you have a single skin/ solid wall construction so i would question the suitability of ewi for your construction type