Can I temporarily insulate a conservatory roof?

Heres mine again

 

That looks great. Gona seriously think about doing this ourselves and with the money saved will pay for some nice new furniture for the conservatory.

Many hanks for sharing.

 

Oooer! That was close! Phew/////

 

Cracking job, Scooob.

 

Hello Good People
First of all may I thank you all for a first class thread and some really interesting reading

Resulting from all your informative feedbacks and having read the thread which stated back in 2006 I am convinced that I can also have a bash at insulating my conservatory roof
I have tried to collate all your suggestions and hope to end up with a workable combination of what may be the easiest solution which will prove to be sufficiently efficient and cost effective

To allow me head off in this direction - may I take the liberty of making a few requests and asking a further questions?

1) Gormac:
As Wendy 1970 and Impsince 85 have noted - unfortunately we have not been able to view any of your pictures (your work descriptions have been a great help but I find it difficult at times to visualise)
Is it possible you can resubmit them?
AD - I doubt that you can get in before Gormac on this one !!

2) Gedvan:
I must admit I do like your partially vaulted setup which effectively lowers the height of the ceiling while creating a larger insulated void between the new ceiling itself and the poly roof
Having looked at the available photographs of your joisting arrangements I am not too sure how to apply support for the joists at the outer end of the conservatory (the end furthest from the house gable)
I appreciate the support at the gable end but am wondering what performs this supporting function at the opposite end and the outer edges?
Do you have any advice (or additional pictures)?
What sizes of joisting did you use (my Victorian style conservatory measures14ft x 14ft at the extremes

3) AD / Pink Connect:
I am also pulled towards the suggestion that PinkConnect has made which is (rather than finally fix UPVC cladding) to screw (say 25mm Kingspan) to the roof beams
I could then finish by applying ceiling paper and heavy emulsion paint similar to the rest of the house
Reading thro the threads I did not see any adverse comments to this basic suggestion from PinkConnect (apart from the initial comments discussing 'floor lino')!
If this idea does not receive a thumbs up I would proceed with the UPVC cladding finish
Pink Connect - what did you finally end up doing?

4) One other General Question:
During my researches and before reaching this most informative thread I was continually coming across the following advice "Do not consider insulating your conservatory roof"!
Reason - your conservatory roof is not designed for the additional weight that such additions would add - subsequently the structure would become unsafe!

5) Scooby:
Thanks for you pictures - really appreciated

6) Finally:
I first started researching the project by reading this U-tube video and was wondering if any of the members have any points of view concerning the 'cross ventilation' recommendation as shown in this link i.e. drilling equi-distant 6mm holes in the horizontal roof support within the imminent 25mm void
Can the good members please add their thoughts?

I do hope that I am not being too much of a pain by asking these questions but I really do want to ensure that our conservatory does not end up collapsing around our feet or I end up making a major cock up which then becomes a costly repair job
I believe that if I continue to follow the advice by you guys I will not go far wrong

Kindest Regards to All

 

BjpScot, that's a cracking video, and the cove there made a thorough job of it.

I can understand his reasons for wanting to add the ventilation holes, but haven't heard anyone else refer to this, not even from 'pro' companies on PooTube describing a similar job.

I suspect that, if you use silvered quilt (or even Celotex which has foil outers), you probably won't have a problem as the sun's energy is reflected. Ok, it might get a bit warm in that layer, but I doubt it'll get any hotter than a whole connie gets on a hot day .

But, this is just my assumption. By all means drill these holes if you are concerned.

As for roof strength, although the poly roofs are lightweight, they are subjected to large forces from strong winds, so are not weak by any means. The horizontal ali roof bars take the weight of a cove* with little problem, so will easily cope with a layer of 9.5mm p'board or PVC cladding.

I don't understand your "I am not too sure how to apply support for the joists at the outer end of the conservatory (the end furthest from the house gable)" concern. There is an aluminium frame running all around the perimeter of the roof above the 'walls', so why can't you screw into these?

(And I've beat that Gormac cove into the weeds...)

(* A 'cove' is an Utter-Hebridian male...

 

Thanks for your reply DA -appreciated
The video is the first part of 3 and basically describes the method that you guys have employed (other than using plasterboard 9.5mm thick) to finish
I was reckoning finishing off with 25mm Celotex instead (you reckon that would be OK?
As a matter of interest can you plaster over Kingspan?
I will have to try and digest Gedvan's jointing arrangement - maybe he will come back to me but I take note of your comments
I really fancy dropping the ceiling height a wee bit but with my conservatory being fairly large I am not 100% sure of joist sizes etc etc
PS
*Maybe Gorvan is just letting you take the Glory ......*

Kind Regards

 

Hi pjb11scott

I've uploaded pics that Gorman sent me

 

​

 

Thanks for the video

We are defiantly going to attempt this. We were quoted £1500 to do ans we have cost it up to cost around £6-700.

 

I personally reckon 25mm Celotex would work fine, and would likely be easier to handle. But, no, you cannot skim plaster straight on to it.

I think I could only recommend one of two approaches to the finish - 9.5mm plasterboard which is skimmed (you could try getting away with taping and just filling over the joints, but I doubt you'd get away with it aesthetically), or else some form of panelling like T&G PVC or even lightweight timber cladding.

I'm not sure what your concern is over joist sizes, unless you are thinking of spanning joists from one side to the other to make a flat ceiling? In which case peeps on here will be able to recommend sizes to span the length you give. But, I'd personally stick with fixing battens to the existing rails.

The vertical roof rails are fairly strong. However, the horizontal ali rail which runs just above the windows around the perimeter (let's call it a 'wallplate') is much stronger and has the window frames supporting it. So, if you wanted to have horizontal joists going from one side to the other, I'd be inclined to use this rail to get your main fixings from. For instance, if you wanted a flat ceiling but a bit higher than the top of the window height, I'd be inclined to fix a batten to that wallplate all around, and then take short lengths sitting on this wallplate for strength but also screwed to the sloping vertical rails for whatever distance you wanted - up a foot or so. Then your proper ceiling joists would go across from these short stubs. Ergo, your wallplate is effectively taking the weight of your new flat ceiling.

 

(I do love it when people say they are going to "defiantly" do something... )

 

Wendy1970
Many thanks for the photos - your help is welcome
The video is the work of Renova2012· - I came across this prior to landing on this forum - it really is a first class effort

DA
Aye I am looking at spanning across the conservatory in a somewhat similar manner to that of Gedvan
Assuming I have the nerve I would prefer to drop the height of the conservatory roofing and create a ceiling at the same height as the rest of the house (our conservatory leads directly into the kitchen so this would not look out of place)
As you state this will effectively create a flat ceiling higher than the top of the window height

Your idea of fixing a horizontal baton around the 'wallplate' and then fixing equal sized vertical ones to provide the final height of the ceiling will be taken on board
Creating the ceiling may be a bit more expensive but I will do a costing and compare

As our conservatory is Victorian design 14ft x 14ft my first reaction is to go for 4x2 main joints - but that decision is for a bit further down the line

Whatever my final decision is (whether to go for the 'traditional system as described by the fellow members or otherwise) in the first instance I still need to fit the 1st set of batons to the poly roof and then attach the Superquilt
On completion of these tasks and at that juncture I will take a step back - assess my progress and then and then decide what direction to take

I now need to see what quantities are required and where I can get the best deals for materials so will spend a wee while on that today

Many thanks to you both for your responses

Bob

 

Hi Bjp.

I haven't actually seen Gedvan's photos - the links have probably been terminated.

So, instead of a fully-vaulted ceiling you are considering having a flat, lowered ceiling - with, say, just a foot or so of sloping sides? In which case I reckon this will be a sod easier to build.

You wouldn't insulate against the existing roof in this case, but place all the insulation in the new ceiling - stuffed between the joists. You'd have a ceiling void above, which will hopefully remain ventilated through the gaps that always exist between the poly sheets and the tops of the 'walls'. (Tho' further drilled holes may well be a good idea, right enough)

It'll be easier as you'll basically have a large flat ceiling and a few short sloping sides to deal with - much easier to board out and skim.

Fit a wallplate all around - you might get away with just 2x1 here. Cut short lengths of - ooh - 2x2s to form the sloping sides bit. These should be 'birds-mouthed' or similar so's they sit on the wallplate neatly, 'cos it's the wallplate that'll be taking the weight of the ceiling. These should also be screwed to the vertical rails. The tops of these short struts should be cut at an angle to make them horizontal. (And all the tops need to finish at the exact same heights!)

Then you choose your ceiling joists - sizes to be determined by the span. Cut these neatly to length and mitre the ends to suit the roof rail slopes. These should hopefully now fit snugly on top of the 'struts' and neatly against the vertical rails, and a long screw skewed into it from the strut.

Neatly cut your Celotex to fit tightly in between all the struts and joists. I'd be inclined to use thin stuff here - perhaps just 25mm thick - so's there's a gap behind the sloping struts for air flow (you can always double it up for the main roof area if you want). Fit the Celotoex so's it's level with the front edges of the struts and joists.

Or, fit 'whole' sheets of Celotex tn the undersides of the struts/joists before the p'board - whole sheets are always better than cutting to fit in between joists. You'd need to allow for this extra thickness in all your calculations, tho'.

Or, go the 'quilt' route. Does this mean you'd have to add further battens afterwards tho'? I mean, does the quilt need room to 'fluff up', or can p'board be placed directly against it? (I don't know...)

Essentially, you want the ceiling void above completely isolated and air-tight from the room below (but still a bit draughty up there...)

P'board, tape and skim.

Cough - don't forget your leccies...

 

Thanks AD - let me digest
You have indeed guided me in a slightly different direction as I was going to fit the 1st set of batons to the poly roof and then attach the Superquilt as directed by the previous threads but as you point out there really is no need as now I look at it as a typical roofing 'attic' so to speak and insulate accordingly
Easier and perhaps a little cheaper
As a matter of interest you will find Gedvan's pictures within thread #106
Now I will print off your last thread and consider your thoughts
My lighting is wall mounted (plus standard lamp) so no implications there other than change present wall fittings to down-light configuration
Holy Moses plenty of room for thought - hope my brain will handle this
Appreciated

 

Ah! You have to 'click' to see his pics! Do'h! That would have saved me quite a bit of writing...

Hmm, nice job by that man. When it comes to how to construct the framing, just go for whichever method you fancy!

However, I do think he's made an error in the way he's insulated the roof. I wonder if he's placed any immediately above the new suspended ceiling too? Even so...

The problem is, some moisture will go through that plasterboard ceiling, and will condense above it because it's still a lot colder than the room below even tho' he's lined the outer shell. The main issue will be lack of ventilation up there - he looks as tho' he's sealed off that upper void, so I fear it'll become pretty damp over a couple of years.

Just seems weird to me.

I am certain you will be better off leaving that void alone (the only exception will be should you wish to add a wee bitty more ventilation, tho' likely not necessary as these polycarb roofs do tend to be a wee bit draughty anyways! Also, if you place the insulation layer immediately against the p'board (or other cladding), you'll have pretty much zero moisture getting through to the void anyway, and any that does will be dispersed by the tiny ventilation up there.

If Ged hasn't placed insulation above his new ceiling, he's missed a giant trick imo. Very surprisingly, as he's clearly on t'ball in other ways.

But, nice job of his. I'd say that's a much 'easier' job that doing the whole 'vault'.

 

Oh, better still, forget a separate insulation layer altogether. Use Thermal Laminate Board to line your ceiling - that's plasterboard with high-value insulation already bonded to it. If you choose say around 50mm thickness, it'll be just as easy to fix as normal p'board (use longer screws!) and will give excellent insulation levels.

Job's a jobbie.

 

Hmm!! loads to take in eh?
I have been looking at both jointing methods but think that I will run the initial prime supporting joints as you have described - that is across the conservatory first
Next I reckon I will run (what I call the secondary joists) from the gable end towards the end of the conservatory - sounds a bit of a higglety-pigglety explanation but! - enough to say I reckon to follow the guide you have provided

Must admit it was Ged's pictures that spurred me into thinking of the flat roof idea - I reckon his looks great

I take your points regarding the required ventilation within the vault and will most probably go for bibs and braces by drilling the 6mm holes around the 'wall plate'
PS
Thanks for the tip regarding 'Thermal Laminate Board' - now I just need to Google and find out all about it
Is this laminate Board fairly light - no problems with weight (think I am paranoid about weight issues) ?

You're a star!!

A lot for fresh fish (albeit an aged fresh fish) like me to take in but am sure I will get there

Regards

 

Whatever approach to the joists you feel is easiest for you.

Your connie has a 4m span. By the time you've go up the roof a bit, that'll be down to - what - 3m or less? I'm sure peeps on here will be able to recommend a suitable joist size - I suspect it'll be 4x2s.

(You could even be cunning and have a central 'purlin' running across all the joists in their middle, and have this suspended from the connie apex. Then you could get away with just 3x2s for the joists, screwed to this supporting purlin )

For your vent holes, don't forget the insect mesh or you'll end up with wasp's nests and worse up there - you'll soon wish for the gentle sound of falling rain on your roof...

TLB is a delight to use. Barely no heavier than the p'board itself, and actually easier to handle as it's more rigid and less prone to breaking. The size of panels you'll be working with will be a doddle in any case.

One point, tho' - you want the insulation layer to be continuous, with no gaps. That'll be tricky where they meet - you'll need some external mitres. What I'd be tempted to do, I think, is to cut them as neatly as possible but without panicking, and fit them all in place with just a minimum of screws first - just enough to hold them in their correct positions.

When they are all cut and in place, remove all but one, run a bead of expanding foam along the joining edge and replace the next panel. Screw. Repeat for the rest. Any gunge that comes through past the p'board face, just trim off with a craft knife before it sets fully - don't worry about what's above! All sealed.

I have to say I like the slightly vaulted ceiling idea - I think it'll look more part of the house, will keep the heat further down, and is just a cracking solution all 'round.

 

AD
Not sure about your new word 'Purlin' yet but will research today
I do have a steel rod that is fixed to (and hangs from the top of) the poly roof - this is fixed at the lower end to 2 horizontal rods ('tie-bars') - not really sure of the function of these tie-bars
I can probably utilise this vertical rod as the horizontal ones will be removed once the roof is in place

Regarding the thermal laminated board - I have been researching this and find that the thermal efficiency of the Basic40 (40mm)is the same as the Plus27 (27mm)
The PLus27 is a little more expensive but I was thinking that the Plus 27 would be easier to handle??
Or do I need 50mm??

One thing that I ask is:
The span of the poly roof vertical panels is 30" - I note that the regulation pitch for joists is up to 24"
Will this 30"pitch be OK??

Thanks as always for opinions and guidance