Conservatory Insulation Options

LessThanSte

Hi everyone.

We have an existing conservatory bolted on to the dining room, with no doors between the two. Having a little one pottering around has made us think about improving insulation - its fairly cold in the winter and needs the heating on to make bearable, in the summer can get hot but is north facing so doesn't get as hot as it could (in peak summer it gets direct sun for c.2hrs each morning and afternoon).

I've had a few quotes, and would value some opinions here.

• parents had a full roof replacement, c.£15k about 5 years ago.
• replacing existing (c.25 year old, we assume) polycarb with (white) insulated panels, c.£5k
• internal insulation i.e. wooden battens and insulating foil added on inside then covered, c.£2.5k

Greenspace are coming soon. I think their panels are something akin to option 2 above but 'better' i.e. lower U value.

The 'best' option that would probably be suggested is option 1, though we dont want to do the 1st option currently given finances, and if we were in that region of costs we'd probably go the whole hog and knock it down and start again with a proper extension). Im slightly concerned about the 3rd option and the potential for leaks etc., though perhaps that can be offset by getting them to replace the polycarb panels when they install.

The suggestion seems to be that full replacement gets you a 'U-value' akin to a proper roof (c.0.2W/m2K), vs c.3 for old polycarb (correct?). Insulated panels suggested around 1. The quote we had for internal insulation also claims around 0.2, though i am slightly skepticle of that (someone suggested it's closer to 2).

Grateful for any views, particularly from anyone who has had any of the above done and can compare before vs after.

Ms_Chocaholic

Do you use the space in the winter? Could you get doors put in between the dining room and the conservatory, it will keep your house warmer.

LessThanSte

We do, but want to keep the two rooms connected. If we did have doors instead, the conservatory would be colder still and I think we'd be looking at the same option (as still use the space for playing with the little one, for example)

WIAWSNB

Hi LTS.

There are lots of lightweight roof cladding materials available these days that resemble tiles and slate, and the existing roof framework should be able to handle most versions, tho' to reinforce the rafters should be straightforward if needed. £15k for this is clearly bonkers, tho', so I would investigate local companies who can offer this service.

Option 2 seems pretty pointless to me - the improvement in insulation will be greatly limited by the thinness of the panels, and the whole roof will remain as draughty as it currently is.

Option 3 is a cracking DIY project, and should be transformative. First ensure the outer roof covering is weathertight - it doesn't leak, does it? - and then remove any foam seals around its perimeter; you want it to be draughty & ventilated up above what will be your new ceiling.

Then you either add new timbers to make a self-supporting roof frame, or you can even bond them directly to the existing ali rafters. Bond insulated board like Celotex/Kingspan to these timbers, 1-2" thick, neatly mitred and with a bead of foam in between the butts to seal them, and tape it all around to make it draughtproof - you want a sealed, insulated shell.

Then add whatever decorative finish you want - lightweight T&G or whatevs. Even embossed/textured paper will do.

If the conservatory has dwarf walls, then consider lining these on the inside with insulated plasterboard - again just bond them in place using adhesive foam or products like Stixall.

Boohoo

@LessThanSte what design of conservatory do you have?

What type of heating and flooring do you have in the conservatory?

Some lean to conservatories can't have vaulted ceilings like I think WIAWSNB is on about because if you start at the lowest point of the roof and the go towards the wall it will be to low to fix a wall plate.

Some photos would explain your situation better if that's possible.

WIAWSNB

Whatever type - full vault, partial vault, or sloping.

Yes, a photo and some basic dims would be useful.

WIAWSNB

Sil just had a complete timber extension room added to her house via the existing patio doors. 4x4m, fully insulated, Shiplap inside and out, timber floors - it's fab, and has transformed her available living space. Two DG windows, and its own DG patio doors to the garden. EPDM roof. £24k.

Pretty sure that sort of local company would readily tackle an insulated roof conversion on an existing conservatory, and for nothing like £15k.

I'd ask on local Facebook pages, LTS, and get some local companies, even good handyfolk, to view, comment, and quote. Come back on here with their ideas.

Section62

https://forums.moneysavingexpert.com/discussion/6688216/conservatory-insulation-options

We have an existing conservatory bolted on to the dining room, with no doors between the two….

If the room doesn't have an external-grade door between it and the rest of the house then you have an extension rather than a conservatory, and consequently full building regulations apply. This includes to any modifications and enhancement of the existing building. If/when you sell you may be asked for the building control paperwork for any alterations.

You'll get advice about low-cost improvements, but adding internal insulation and/or cladding to a conservatory-type structure needs to be done with great care. Bodge jobs using glue, and alterations made by people who don't know what they are doing, can be risky - and in this case there's risks from condensation and mould, fire, and physical trauma from bits falling on people.

If this is a place your little one will be playing then you need to take extra care to ensure the job is done properly. If you want an extension rather than a conservatory then think seriously about the idea of demolishing and starting again. If it will take a while to organise/save up for an extension, then work out how much heating you can buy for the cost of bodged-up insulation. Heating is expensive, but building materials are not cheap.

LessThanSte

Hi folks,

The conservatory was installed in c.1995, possibly at the same time as the house was built (or shortly thereafter). There were originally wooden doors between it and the dining room - but these were removed by the previous owners. I don't recall anything being flagged during surveys etc. when we bought the house 5 years ago.

Its an Edwardian style conservatory, c.3.5x3.5m. Has 2x radiators and a wooden floor.

When i mentioned £15k for a 'replacement roof', this was in a conservatory that was larger than ours, but yes was a replacement of the roof bars etc., and then install of a (i think metal) tile-effect roof, then insulated inside and plastered. Im led to believe that if we did something like this we would almost certainly need to extend a wall to support the structure. Either way, its not the plan.

So the two options - replace polycarb with insulated panels (see CosyPanels/PanelX examples), or internally insulate. Everyone i've spoken to suggests that internal insulation, whilst simple and cheap, is fraught with danger and almost always ends up with leaks and/or damp resulting from drilling in to to the roof frame. Whereas the panel solution replaces the polycarb.

The do-nothing is an option of course - theres nothing fundamentally wrong with what we currently have, only that we might need to turn electric heaters on occasionally in the winter to keep the conservatory and the dining room (and the rest of the house, if the dining room door is open) at a decent temperature.

WIAWSNB

Lining the inside with rigid insulation is not fraught with anything, if done sensibly.

You'll have an outer weatherproof covering - as with all roofs - and then a lightweight insulated & draughtproof lining/shell on the inside.

If the outer covering leaks, you fix it - as with any roof.

You do not have to screw into the existing ali frame if you do not want to; you either bond to it using a building adhesive (which you will not be able to tear apart) or you construct a separate lightweight timber frame within.

Of course if this is built by an truly incompetent person who hasn't the first idea what they are doing, then there could be a 'risk'. Just as if an incompetent person were to incorrectly assemble an outdoor swing or slide or trampoline.

But the risk is overstated. This is an easy task, well within a decent DIYer's abilities, and definitely within a general builder or chippy's remit.

What you currently have does not appear to remotely conform to Building Regs (it should not be connected to the house's CH, and it should have exterior quality doors separating them), and this should have been flagged up during the purchase. But, what actual difference would flagging these breaches have made to your decision? No, not to mine either; you liked the house, and it has a nice conservatory fitted. Yes, this currently consumes far too much energy during cooler months, but this can be largely addressed. I mean - would you rather not have this conservatory at all? Of course not.

Alternatively, just install 'external' doors in the opening betwixt the house and 'ory, and accept that you won't use it on dull cold days with no solar gain. Or, keep running the rads and accept you are paying excessively for it.

LessThanSte

As above, the do-nothing option of keeping as-is is on the table, depends how much the proposals ultimately come out as. Its not terrible. Just not ideal.

The insulation option looks something like this; Conservatory Roof Insulation Process - How It Works

I.e. timber frame attached to the existing frame, and then insulation (appears to be a blanket) to fill the new space in, then a 'cover' of some form. Youtube shows most of those wooden frames fitted by screwing in to the existing frame. I guess, as you suggest, bonding it would avoid having to drill holes and would be preferable. In any case, it leaves the 'outer' layer to be the potential problem - its c.30 year old polycarb (i assume) which when provided an insulation layer immediately below would (i assume) cause the polycarb to become brittle over time, and any assocaited damage/leak would then result in a much bigger problem (a leak in the polycarb currently installed could be fixed by simply replacing the relevant panel).

The panels - a foam insulation sandwich with upvc or similar outer and inner faces would simply replace the existing polycarb.

Anyway, going around in circles. Im not especially worried about whether its DIY'able or building regs compliant etc. I'd really appreciate views of anyone who has either replaced polycarb/glass roof panels with rigid foam insulated panels (ala CosyPanels / PanelX) or internally insulating (something like SnugCore), including a view on whether it really made any noticable difference.