Conservatory Insulation Options

LessThanSte

(Quoted post removed by Forum Team)

This is helpful, thanks.

What would you expect in terms of U value between panels (PanelX website suggests 25mm panels are c.1) and an internal insulation option? I was also thinking that 0.2 sounds too good for the latter, what would be reasonable, in your view?y

Full replacement was c.£15k on parents conservatory, but that was half as big as ours again (5m x 5m ish). It also had a full height wall along one side, whereas ours only has the dwarf wall (c.1m) around the footprint. I guess the number would be lower than above, assuming i dont need extra walls etc. I think, if this was the route we went, we'd need to install a door between the rooms again - but that is impractical for how we want to use it. Or in other words, if we dont want to add a door between the rooms, is it right to say that building regs would not sign off on the work?

TELLIT01

We had a lightweight roof installed on our Edwardian style conservatory about 5 years ago and that cost £8k for a conservatory roughly 3m x 4.5m. We did have one quote of £15k for the identical roof from another company. Even with that roof, and the conservatory only now having glass on the NW facing wall, I wouldn't want to do away with the doors between the house and the conservatory. We have underfloor heating in the conservatory which is set to come on at 14c.

The roof is more effective at keeping the place cool in summer than at keeping it warm in winter.

LessThanSte

Just following up on the building regulations point, having been reading a bit about it this afternoon.

Where do we stand currently on the basis that;

1. the conservatory has planning approval, secured in 1995, and built around the same time
2. since then, previous owners removed the doors between conservatory and dining room (and covered the fixing points with a wood strip. Radiators were also installed as part of the central heating system (not sure if installed with the system when it was first installed during construction in the mid-90s, or added on later).

I think its the case that, if we were to replace the semi-translucent polycarb with an opaque panel or adding insulation under the polycarb, this would require a building regs approval. What then would be the outcome, on the basis that point 2 above presumably means it not compliant? Or is there some form of 'its been there a long time, so can be regularised' allowance?

Or in other words, if i were to get some simple insulation installed, i could find myself on the hook for not complying with building regs and have to reinstall doors/remove rads, etc.?

Section62

https://forums.moneysavingexpert.com/discussion/comment/82182558#Comment_82182558

But the risk is overstated.

With respect, I don't think you have the qualification to say that.

For example, you've suggested bonding the internal insulation and supporting materials to the conservatory frame rather than using mechanical fixings. You've mentioned the use of Stixall.

You may not be wrong to say "which you will not be able to tear apart", but this neglects the effect of fire. Stixall is not fire-rated. Standard Stixall is only rated up to 100C.

In a fire situation the chosen adhesive might fail quite rapidly, allowing the ceiling 'structure' to collapse down into the room. This could happen when the conservatory is nominally still usable as a means of emergency egress, either blocking the exit route or (in the worst case) falling on people trying to escape and thereby trapping them in a burning building.

You could say "but what are the chances". But that is partly why the building regulations are there. We could look at various aspects of Grenfell and say "but what were the chances"… though would be doing so with the knowledge that those things did happen.

Someone who knows what they are talking about, and is qualified to assess risk, would know that ceilings should have mechanical fixings, and if adhesives are used on things which might block a route that may be required for emergency egress then they need to have a suitable fire-rating.

Using internal insulation in a conservatory introduces considerable risk of the 'chimney' effect - especially if draughtproofing has been removed (as suggested) to get a flow of air between the insulation and conservatory outer skin.

Far from an "easy task", adding insulation to an existing conservatory needs to be designed properly by someone who understands the risks (and benefits). What you are proposing as a DIY option is a potential deathtrap… and the average hired handyperson may do no better.

Section62

https://forums.moneysavingexpert.com/discussion/comment/82183089#Comment_82183089

Or is there some form of 'its been there a long time, so can be regularised' allowance?

You can apply for work to be regularised at any time after it is done, you don't have to wait for years before applying. The time factor with building control is on the timescales where enforcement action can (normally) be taken by the council. It used to be 12 months, but is now 10 years.

(Planning is different - after the enforcement period has expired you can safely apply for a certificate of lawful development)

in other words, if i were to get some simple insulation installed, i could find myself on the hook for not complying with building regs and have to reinstall doors/remove rads, etc.?

It is complicated, and only your local council can tell you exactly what they might do (but asking them may be a bad idea).

My expectation is that the council would probably deem the door removal as beyond enforcement, but would treat the 'conservatory' as an extension for building control purposes. This means the lighter-touch requirements available for a normal conservatory wouldn't be available - the new work you'd be doing would have to comply with the regulations as they apply to extensions. This would mean (for example) you can't just add a little bit of insulation, you'd have to install the insulation the BCO requires. You may also get tied up with the rules where you are changing more than a certain %age of a roof or extenal wall that you have to add insulation as well.

This is a fundamental issue that buying a building with non-compliant alterations comes with… you may be free from the risk of enforcement (and an indemnity policy can protect you financially), but when you want to make further alterations the non-compliant work can cause problems.

Worst case, if the door removal and radiator fitting was done later than we might be guessing, then it may still be within the 10-year enforcement period.

Swipe

Have you taken into account the loss of daylight with an opaque roof? I had a conservatory backing on to a kitchen and it was awfully dull when it was covered in snow. I'd throw a tarp over before you do anything and see how dull it becomes.

molerat

A house behind us had theirs done by a local well respected windows / conservatory company and it was externally over-boarded with OSB, covered in membrane and topped with lightweight plastic / composite "slates" of some description. Don't know what they had done internally though.

Boohoo

I think before you do anything to the conservatory you should try and see if anyone else has had this thing done and try to have a look at the end result to see if it is any good.

Not sure if the company that gave you a quote would let you look at on of their completed jobs.

XRS200

I had a lightweight roof done. Similar size to yours. £5,600. Very glad I did.

Remove polycarbonate etc

Mechanical fix 4x2 timber to skeleton

Fit 6x1 timber to truss ends

Install new fascia gutters downpipe

Fit new OSB and membrane

Install new counter and tile battens

New metrotile or easytile roof incl hips and ridge

Fit new lead flashing

Fit 100mm insulation boards

Strap ceiling and fit 12.5 mm gyproc

Install 6 downlighters and dimmer

Plaster ceiling

Swipe

These non-DIY prices to insulate are probably more than the original old conservatories cost to have built.