GlosRob

1. GlosRob Member
   I am going to start my roof project in the next couple of weeks. My conservatory is a simple lean to. I am planning vertical battons, sheet then cladding so it should be fairly easy. I do have a couple of questions though.
   
   My roof bars appear very close together should I batton each or go every other one ?
   
   I have a sloping window at the one end and I am wondering if it would be easier and more tidy to brick or plaster board it up. I think once the batton and cladding is on it will but up to the glass and look a little silly ?
   
   Regards
   
   Rob
   
   
   Hi Rob.
   
   Possibly best to start a new thread for your own project - 'cos this one is getting beeeeeg.
   
   Anyways, I've no idea what type of roof bars you have - they appear very thin. What do they look like from the outside?
   
   I wonder - for such a narrow room - would you be best off replacing the roof completely? Ie - proper timber rafters packed with insulation and a MDPE or similar external finish? You could then make it to clear the inside windows, it would be solid, well insulated, etc.
   
   Should you go for an 'inside' job as you propose, I don't think the end window is a problem; however much it is covered by the time you finish, just make up a piece of white PCV trim to fill the gap and tidy up between the glass and the new ceiling - almost as tho' you've lowered that top window rail.
   
   But, them roof rails - I just dunno...
   
   GlosRob Member
   New
   
   I had originally thought about a complete new roof but I was worried if the structure would take the weight. I guess out of choice I would opt for a complete new roof but the internal route would be quicker and cheaper.The size of the con is approx 2.5 x 6.0m and the roof bars look like they are about an inch wide.​

 

I wouldn't worry about the structure being able to take the weight of a new roof, as on one side you have a brick wall and on t'other you fit a timber wall plate to take the load which is then supported by the window vertical bars.

I've no idea what kind of roof you currently have - I've never seen 1" wide bars set so close together before. They don;t look particularly strong for a 2.5m span, and are probably enough just to hold up these narrow poly panels. I don't think I'd go that route in this case, not unless you build a roof frame that'll support itself, but that will lower your ceiling height a goodly 5"?

 

And you can design your new roof to have a couple - or more - of proper d-g glass panels in it - make it a striking feature and allowing in more sunlight, whilst being thermally nifty too.

 

No, just on the two long sides. A 'wallplate' is usually a thin flat piece of timber - say 4"x1" - which sits on top of the brickwork on a house wall. In your case it wouldn't be sitting on top of the 'wall' but be fastened using screws to the brick wall on one side and to the horizontal top aluminium bar on the other. The one fastenhed to the ali bar would be more substantial - say 4x2. You'd then simply use joist hangers to attach the joist to these.

You could, of course, also have just a thin wallplate sitting on top of the ali bar, and then sit your joists on top, but there are two issues with doing this; 1) the joists will be sitting higher than expected, and 2) a thin wallplate would allow the weight of the new roof to act on the actual top window frame as opposed to the vertical frame sections.

Your call

But I just can't see using the existing roof bars.

 

Looking at your pics, you have a brick wall on one side and glazing on t'other?

On the brick side, I had assumed that this wall extended upwards beyond the height of the connie roof, so the roof panels were sitting on that just-visible wall-rail. However, looking out through a back connie window, perhaps the connie roof panels sit on TOP of this brick wall instead?

Either way, the essential process is to sit the new rafters where the current roof panels are, provided they have enough of a lip to make secure.

The same can happen on the glazed side except you need to consider that the new roof will be much heavier than the old poly panels, so the horizontal rails above the windows may not be strong enough - they could theoretically sag and cause problems with the top openers. Of course, it could be that the top rail is plenty strong enough for this new roof, so could be fine, but obviously I can't tell that.

Hence me suggesting some form of 'wallplate' mounted, and screwed, along the top face of that existing top rail - it'll act like an extra 'lintel' reinforcing the top ali rails to prevent them from sagging.

If you then fit your new rafters sitting where the current poly roof is, you could probably get away with lining it underneath with just 25mm or 35mm thick Celotex-type insulation, and then whatever finish you wanted - cladding or whatever. If your desired finish is a plaster skim, then line the underside with Thermal Laminate Board which is plasterboard with insulation already bonded to it. Thinnest overall thickness is 35mm. That way the new ceiling will only come down 35mm or so more than the existing ceiling, so it'll look good and not encroach on your window panes.

Then you'd need to fill in between the rafters with some other insulation before overlaying the top outer surface with whatever finish you will choose, such as MDPE.

That's the basics. All I have is the basics 'cos I'm not a roofer.

And you are asking me...

 

Eek, only just seen this. 3" deep? Probably pretty strong, then - it's the 'depth' that matters, as you know.

Ooookkaaaaay, then...

Do you know if these sections are hollow and sealed to the outside elements? Ie - could you drill and tap a screw into them from underneath (inside the house) without getting yourself wet?

If so, then you could almost certainly get away with lining the inside with lightweight insulation board like Celotex/Kingspan (foiled on both sides) and then finishing off with whatever finish you are after. This could be PVC cladding, or even something I've seen on another thread on here - it's a roll of insulation material you paste on to walls (no, not the expanded polystyrene stuff!) and which leaves a finish good enough to paint. In fact it can be used to not only add useful insulation to walls, but to tidy up rough-looking finishes.

I'll link to it if I can find it.

Hmm, could be very simple, very cheap, and very something else.

Hopefully successful...

 

Our lovely Teabreak cove linked to it in another thread: http://www.coveryourwall.co.uk/wallrock-thermal-liner.html

 

Wanna easy job you can complete in a weekend? Get some sheets of 35mm Celotex/Kingspan (foil both sides), a few tubes of StixAll, and a couple of rolls of that wallrock liner.

Clean your ceiling rails. Cut your Celotex to size - make them a snug fit. Run beads of Stixall along them and press the sheets home. If the sheets are warped, you may need to support them whilst the Stixall sets. They won't shift afterwards.

Seal between the sheets with sealant and/or tape, and also around the wall perimiter.

Finally adhere the wallrock covering over them.

Job done.

I bet it'll work.

But I offer no guarantees...

The next person to come on here and ask about 'insulating your connie roof' will be directed to this thread with no further comment...

 

I'm pretty sure what I would do in your case is to bond the Celotex straight to the rails - not the poly sheets.

Usually you would need to worry about leaving a ventilated gap so's any condensing moisture can be ventilated out, but I'm thinking that if you seal between the Celotex sheets properly - using the correct tape - and also against the connie sides - again using tape of sealant - you will have completely isolated the teeny gap above the Celotex from the room below - so no moisture-laden air can get there.

Also, the sun will largely be reflected by the foil layer so things shouldn't get too unpleasant in that gap (a few mm) to cause problems, but it will still become warm so will hopefully keep any minute bits of moisture at bay.

This is all theory, you understand...

Of course, if your poly roof fails, then the only way to remove the Celotex sheets to gain access will be by destroying them...

If you are confident that your poly roof is in decent order, then I know what I would do...

Simple, cheap - and almost certainly very effective.

 

Get lots of tubes of StixAll or a very similar product. It has huge adhesive strength and will also fill gaps.

Check - it might need one surface to be porous or absorbent, I'm not sure. So you may have to use something else. But I wouldn't use sili as such as it isn't primarily designed as an adhesive.

I'll lay odds that this will work a treat - it'll certainly be simple and relatively cheap.

Keep us posted on your progress .

 

Sorry - didn't see your last Q.

Anyways, you don't want me saying 'not much difference betwixt them', do you?

But there ain't .

Well, it obviously will make a difference, but not as much as you may have assumed.

Think of it this way; the 35mm Celotex will make a HUGE difference compared to what was there before. Ooh, let's guess - 10 times better insulation value than just the roof? Ok, maybe even 20. I dunno - chust guessing.

Now add the same thickness of insulation again on top - how much better will this be? Fractionally. Because the 'first' layer had already done the bulk of the heat blocking - say only a 20th of the heat passes through the first layer, then the second layer can only help block the 1/20th bit that has travelled through; it'll reduce a 20th by a 20th = only a 400th improvement.

Ok, I made all that up - but it got you thinking...