Tue, 14 Jul 2026 16:51:57 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36135#Comment_36135 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36135#Comment_36135 Wed, 22 Oct 2008 19:23:17 +0100 mrswhitecat
If you’ve been following my story, you will know it’s not my fault that we are building this particular house and the design has nothing to do with me. Neither do we benefit from being able to talk with the ‘conceptual’ architect as he appears to have disappeared off the face of the earth.

I do have the benefit of :

- 1 x experienced and competent builder
- 2 x experienced and competent architects
- 1 x experienced and competent structural engineer

Nevertheless, I seem to be getting whiffs of unease.

The issue is a 714 cm x 909 cm flat roof or ‘solarium’. This is bounded on one side (call it East) by the single storey salon (in which the nice fat trusses are now sitting) with a 4-sided 30% pitched roof and chimney. It is bounded on the South side by a garage. This is a separate structure built on a slightly lower ground level and has a 30% pitched roof on 1 south facing plane (on which the solar panels will be fitted). The apex of this roof is higher than the flat roof so it forms a barrier so you don’t fall off the flat roof and the garage wall creates a bit of privacy (easy access too to the solar panels). West side is open and fronts the house – iron railings. North side is the first floor part of the house with access to the solarium and then a bit looking into an inner courtyard – iron railings. The engineer’s drawing shows a 1% slope North to South ie from the house 1st floor towards the wall that constitutes part of the garage.

Gutters and drain pipes don’t exist in Provencale architecture, the roof line is supposed to extend far enough out from the building so the rain falls far away from the walls. My quote, however, provides for 4 gargoyle type things – although no one seems to know where they might go (not shown anywhere in the engineer’s drawings). Recently the builder was talking about getting the plumber to quote for something in zinc (although it was not clear to me what he had in mind) although he has now said he thinks we can do without.

I’ve bookmarked the ‘energy black hole’ thread and also been a close follower of the ‘lead’ thread. However, I thought my roof could do with a bit of looking on by the forum.

Issues to me are :

- I do not want leaks.
- I do not want puddles
- I do not want cascades
- I do not want huge energy losses

I would also like it to be :

- safe
- aesthetically pleasing
- low maintenance
- practical

If you look at the ‘trusses’ thread you can see pics of the flat roof.

See below for what is happening so far on the solarium / salon roof join ...

I haven’t seen pics yet of what the solarium / garage roof join looks like.

My question is : what sort of drainage should I be looking at and how will this work over the insulation and stone tiles that will be fitted over the concrete slab that has been built.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36136#Comment_36136 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36136#Comment_36136 Wed, 22 Oct 2008 19:24:29 +0100 mrswhitecat https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36240#Comment_36240 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36240#Comment_36240 Thu, 23 Oct 2008 17:46:00 +0100 CWatters
I'll try and sketch something in a moment.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36241#Comment_36241 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36241#Comment_36241 Thu, 23 Oct 2008 17:57:54 +0100 CWatters http://img239.imageshack.us/img239/9412/save0042lr2.jpg

The spouts can be cast from concrete and the trenches lined with lead or zinc if you builder knows the man for that.

Perhaps add a low wall at the front and slope the flat roof towards one of the channels.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36254#Comment_36254 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36254#Comment_36254 Thu, 23 Oct 2008 19:05:58 +0100 mrswhitecat
Your drawing deploys the 4 gargoyles perfectly and explains the 'getting the plumber to quote for zinc'.

Should we consider sandwiching the concrete slab between insulation do you think?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36255#Comment_36255 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36255#Comment_36255 Thu, 23 Oct 2008 19:11:07 +0100 mrswhitecat
Oh dear, .tifs aren't acceptable, so I'll have to change it.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36256#Comment_36256 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36256#Comment_36256 Thu, 23 Oct 2008 19:26:12 +0100 mrswhitecat
The little 'X' on the solarium is what was to have been a roof lantern - now ditched owing to costs.

What looks like Velux windows are supposed to be the solar panels on the 1-slope / lean to garage roof.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36258#Comment_36258 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36258#Comment_36258 Thu, 23 Oct 2008 19:32:10 +0100 CWatters
Concrete roofs aren't very common in the UK. If it were over here I'd be thinking of putting the insulation on the inside to stop cold bridging (eg to stop the concrete conducting the heat horizontally to the outside).

The levels do look difficult to me. Normally I'd expect the pitched roof to drain onto the flat roof or into a channel between the two. You need something (normally a step down) to stop water flowing back up/under the tiles on the pitched roof. In the UK you could also get snow/ice/leaves on the flat roof that could raise the level of any water on it.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36259#Comment_36259 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36259#Comment_36259 Thu, 23 Oct 2008 19:39:07 +0100 CWatters
Typically when you have a valley between two pitched roofs you form a little lead lined trench as I've described and extend the lead up the slope of each side to allow for build up of snow etc.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36526#Comment_36526 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36526#Comment_36526 Mon, 27 Oct 2008 09:40:51 +0000 mrswhitecat
I'm not getting pics yet of how the garage side of the solarium is looking but these show how things are panning out on the 4-slope salon roof side.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36527#Comment_36527 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36527#Comment_36527 Mon, 27 Oct 2008 09:42:52 +0000 mrswhitecat https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36577#Comment_36577 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36577#Comment_36577 Mon, 27 Oct 2008 16:55:18 +0000 marktime ]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36581#Comment_36581 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36581#Comment_36581 Mon, 27 Oct 2008 17:40:14 +0000 mrswhitecat https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36582#Comment_36582 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36582#Comment_36582 Mon, 27 Oct 2008 17:47:37 +0000 JackyR
[edit] My goodness - they're still called putlogs! http://en.wikipedia.org/wiki/Scaffolding#Putlog_scaffold]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36642#Comment_36642 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36642#Comment_36642 Tue, 28 Oct 2008 14:44:41 +0000 mrswhitecat https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36651#Comment_36651 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36651#Comment_36651 Tue, 28 Oct 2008 17:05:14 +0000 JackyR The joy of Wikipedia...]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36800#Comment_36800 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36800#Comment_36800 Thu, 30 Oct 2008 18:18:30 +0000 mrswhitecat https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36835#Comment_36835 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36835#Comment_36835 Fri, 31 Oct 2008 10:29:16 +0000 ludite ]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36879#Comment_36879 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36879#Comment_36879 Fri, 31 Oct 2008 21:45:15 +0000 Windswept You write: "If it were over here I'd be thinking of putting the insulation on the inside to stop cold bridging (eg to stop the concrete conducting the heat horizontally to the outside)."

This would not be a good move, if any cool or cold weather is expected.
Placing the insulation below would create a "Cold concrete-Decked Roof", which induces a serious risk of interstitial condensation. In Scotland they are outlawed, while in England they are severely frowned upon. Most commonly used in poorly-designed domestic extensions with a timber structure, where Building Regulations stipulate that such a Cold-decked roof should have 'full and adequate ventilation' - of each and every joist void(!)

In the case of a concrete deck, there is no ventilation possible/available, which will lead to gradual and cumulative condensation and water buildup in the concrete, as well as putting it outside the Bldg Regs.

Provided that it is properly-specified, the Warm-decked roof will prevent condensation in all but sauna conditions.
Another post follows . . . .]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36880#Comment_36880 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=36880#Comment_36880 Fri, 31 Oct 2008 21:46:00 +0000 Windswept A small amount of thermal bridging is a lower priority, I suggest. Besides, it can be overcome; see BRE Report 262 Thermal Insulation: Avoiding Risks. This was updated to the third edition to comply with Building Regulations Parts L2 & J:2002, and is still applicable after Parts L2:2006.

BTW, the location looks idyllic!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=37044#Comment_37044 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=37044#Comment_37044 Mon, 03 Nov 2008 13:04:59 +0000 CWatters https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=37060#Comment_37060 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=37060#Comment_37060 Mon, 03 Nov 2008 15:26:04 +0000 mrswhitecat
When last we spoke Archi1 described a spray on foam insulation on top of the concrete slab which would be shaped when set. Doesn't sound at all 'green' to me ...]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=37842#Comment_37842 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=37842#Comment_37842 Tue, 11 Nov 2008 15:10:10 +0000 mrswhitecat
My assumption has been that either individually, or collectively my consortium of builder, archi1, archi2 and structural engineer will have made a decision about what to do about drainage, waterproofing and insulating the solarium roof - bearing in mind very flat footed hints and the despatch of documents giving u-value calculations ...

Could it be that they are expecting me to tell them what to do? I hope not!

PS JackyR - they're calling the gargoylly jobs 'barbacanes' - very medieval sounding don't you think.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=37862#Comment_37862 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=37862#Comment_37862 Tue, 11 Nov 2008 17:58:01 +0000 JackyR http://fr.wikipedia.org/wiki/Barbacane. Mais pas des bananes!

Hmm. Perhaps waterspouts are a modern usage...]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39514#Comment_39514 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39514#Comment_39514 Thu, 27 Nov 2008 21:14:19 +0000 mrswhitecat
(Rant commencing) : What I can't understand is, I haven't changed anything. It's not as if suddenly I've turned up and said "this is a nice space, let's not put a proper roof on it", it's been on the plans since dot, minus dot even as it's the design that 'came' with the building plot. Anyway a 'type' who I believe is going to be doing our external render was sur place and had a sketch on the back of an envelope, which, when it is written in neat will be rubber stamped by archi-2 but I'm still really no wiser or assured that I'm going to end up with a well insulated, leak free flat roof that drains well and appropriately. An added concern is how to fix the guard rail so it doesn't wobble but doesn't compromise the sealant.

A couple of plombiers who happened to be sur place at the same time, obliged by knocking out a bit of agglo to release the build up and create a waterfall. Observing the mix of water + electrically operated angle grinder was excruciating ...]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39544#Comment_39544 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39544#Comment_39544 Fri, 28 Nov 2008 08:28:38 +0000 CWatters
http://www.fascias.com/media/180221_180.jpg
http://www.fascias.com/media/180223_180.jpg
http://www.fascias.com/media/flat_roof_railings.jpg]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39604#Comment_39604 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39604#Comment_39604 Fri, 28 Nov 2008 16:22:45 +0000 Sally M
Best of luck to you Mrs Whitecat!

Sally

PS Have you looked at Roofkrete for your flat roof?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39608#Comment_39608 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39608#Comment_39608 Fri, 28 Nov 2008 17:34:19 +0000 JackyR http://www.nicecupofteaandasitdown.com/]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39670#Comment_39670 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39670#Comment_39670 Sat, 29 Nov 2008 17:30:53 +0000 CWatters http://www.cakes-direct.co.uk/ They claim to have delivered to ships at sea :-)]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39770#Comment_39770 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2787&Focus=39770#Comment_39770 Sun, 30 Nov 2008 22:12:51 +0000 JackyR