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Cleaning Flat Roof


Onoff

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2 minutes ago, Onoff said:

It was polyurethane liquid waterproofing systems was thinking of. Seems you lay a mat down as you would with fibreglass etc. 

Think this is the system that someone on here once used.

https://www.apolloroofingsolutions.co.uk/market-page/liquid-coating/

 

3 minutes ago, Onoff said:

Only colour here is brown mind?

How do you get brown in the sun?

"Come on Brown, it is lovely out here"

 

 

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4 hours ago, Onoff said:

 

@MJNewton used Desmopol I found from some searching.

 

How's it standing up?

 

Yes, all fine thanks. It's only been 18 months though so maybe a bit early to comment on longevity which is probably what really matters. It's been really tested though over the past year with the rain, and the fall isn't the best (builder made an error with the firrings.... grrr - still winds me up) so if there was an issue I'm sure I'd have seen it now.

 

I'd definitely use it again - easy to apply (a roofer did mine but next time I'd DIY) regardless of complexity if surface/upstands/etc, no seams, tough yet elastic etc. The only things that do bother me about it is 1) hardly anyone else seems to use it (the manufacturer told me they sell very little to the UK compared to other countries and, for what it's worth, stating that the UK market does tend to hold on to its traditional building methods so it's been a tough market to break in to), and 2) I do wonder if Desmopol is all that different from those 'quick fix in a can' paint-on roof repairs that even the manufacturers state are for temporary use only. That said, Desmopol does have a BBE certificate and comes with a 15yr (or is it 25?) guarantee that can be extended 5yrs at a time by an additional coat over the old one every 10(?) years so I'm as confident as I would be for any flat roof covering I think.

 

Here's a pic (of the roof lantern really but's got most of the roof in) after around a year:

 

20181125_105347.jpg

Edited by MJNewton
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18 minutes ago, MJNewton said:

 

Yes, all fine thanks. It's only been 18 months though so maybe a bit early to comment on longevity which is probably what really matters. It's been really tested though over the past year with the rain, and the fall isn't the best (builder made an error with the firrings.... grrr - still winds me up) so if there was an issue I'm sure I'd have seen it now.

 

I'd definitely use it again - easy to apply (a roofer did mine but next time I'd DIY) regardless of complexity if surface/upstands/etc, no seams, tough yet elastic etc. The only things that do bother me about it is 1) hardly anyone else seems to use it (the manufacturer told me they sell very little to the UK compared to other countries and, for what it's worth, stating that the UK market does tend to hold on to its traditional building methods so it's been a tough market to break in to), and 2) I do wonder if Desmopol is all that different from those 'quick fix in a can' paint-on roof repairs that even the manufacturers state are for temporary use only. That said, Desmopol does have a BBE certificate and comes with a 15yr (or is it 25?) guarantee that can be extended 5yrs at a time by an additional coat over the old one every 10(?) years so I'm as confident as I would be for any flat roof covering I think.

 

Here's a pic (of the roof lantern really but's got most of the roof in) after around a year:

 

20181125_105347.jpg

 

I'd say it's likely superior to the acrylic roof repair compounds. I've tried a number of makes Aquashield, Cromapol, Flexacryl etc. On my crap felt roof (see the other thread) they all give up after a while. It's a yearly redo job. I might be being unfair to them as the substrate they are being put on is basically live! 

 

Where's good to buy Desmopol from then?

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12 minutes ago, Onoff said:

Where's good to buy Desmopol from then?

 

Good question; it doesn't seem to be all that widely available when I looked around for where I might get it from in future. I know my roofer got his from Raven Roofing Supplies although there's no mention of it on their website (which is odd as they do training courses for it too). I'd get it from there as they's local but I'd suggest others contact Eagle Insulations as they are the UK distributor I think.

Edited by MJNewton
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Just now, MJNewton said:

There was an 18mm OSB deck and he put matting just over the joints. 

Makes sense, lot less fiddling about.

Almost the same as my idea of GRPing a flat room.

Just do the joints on site.

 

Edited by SteamyTea
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2 minutes ago, MJNewton said:

Slight correction: it was actually a ply deck (the OSB was used below the insulation). 

Be interesting to see how it works on OSB, someone one here wanted to know what the best paint for OSB was.

 

Just had a look at @Onoffvideos.

Roof really are made in a most ridiculous way.  Almost as if they are made from the leftovers on site.  I am surprised that there is not a modular, mass produced in a decent factory, system.

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I don’t like flat roofs generally but have done quite a few GRP roofs and never had a problem, bite the bullet, do it properly, re deck with GRP sealed sheets and GRP the joins etc when fitted, you won’t regret it.

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Here is my suggestion.

 

I hate, as in really really hate, flat roofs.

 

To take the small gable away, and make it a big flat roof I think would look just wrong.

 

How about make the whole lot over both dormers a low pitched sloping roof, sloping from the existing ridge down to the gable edges.  It will be too low for tiles but something like box profile or standing seam would do it.

 

I would strip it all bare, replace any all the rotten wood and re frame it with decent insulation and put the pitched roof on.

 

I wouldn't want to attempt that without scaffold.

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5 minutes ago, ProDave said:

 

How about make the whole lot over both dormers a low pitched sloping roof, sloping from the existing ridge down to the gable edges.  It will be too low for tiles but something like box profile or standing seam would do it.

 

 


even better idea for you, make it into a double eyebrow dormer as they are quite common around you and would fit right in ... soon have all the profiles done in CAD if you crack on this morning ...

 

3116BF83-9140-40F1-9EB9-D66B987CFA0F.jpeg.f424ca605bbafdda5fe69332f3193e40.jpeg

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31 minutes ago, ProDave said:

Here is my suggestion.

 

I hate, as in really really hate, flat roofs.

 

To take the small gable away, and make it a big flat roof I think would look just wrong.

 

How about make the whole lot over both dormers a low pitched sloping roof, sloping from the existing ridge down to the gable edges.  It will be too low for tiles but something like box profile or standing seam would do it.

 

I would strip it all bare, replace any all the rotten wood and re frame it with decent insulation and put the pitched roof on.

 

I wouldn't want to attempt that without scaffold.

 

I really like the idea of a ditching the pitch but didn't come round to initially. Especially with a hatch in the middle for access. Too many years working on roofs I guess makes it seem "normal"!

 

A low pitch, sloping roof was my very first idea. Until that is I started thinking about having weighted PV trays up there! Just seems super practical to hop up from the inside and wash & maintain the panels, clean the roof off. 

 

Yes, edge protection is a big concern especially if I have my lad up there with me. The couple of times I've had him up there I'm shouting at him to stay in the middle/face the edge all the time. If the big "rip off / redo" happens I'll likely screw some cranked, angle iron uprights through the tiles to the vertical corner 4x4s that form the dormer. Think too there is one mid each long elevation. I'd then string a  ratchet strap type fall protection strap all around. That's a busman's job for me tbh. Stuff is cheap as chips:

 

https://www.ukratchetstraps.com/collections/fall-protection-straps

 

Might have said before but I managed to get the original dormer extension drawings from the district council. Really, really poor copy as taken off of a microfiche but better than nothing. They gave it to me foc which I thought was decent, they're not all bad! (I did then ask if I could get an electronic copy of a scan of the microfiche to try and blow it up myself but they never came back to me).

 

Very, very roughly starting to cost this up, all prices inc VAT:

 

Desmopol is £213.84 / 25kg. Coverage is 1.5 - 2kg / m2. A tin then would cover 16.67m2 .Area is nom 64m2. So 4 tins, call it £1000.00

 

Desmoplus Accelerator at 2L per 25kg tin. I need 4 at £68.04 each £272.16

 

Tecnotop 2C is recommended over the Desmopol to improve UV resistance, traffic resistance (important if i had a central access path and was siting pv trays I imagine). It's £136.08 for 5L. Calculating the coverage; 150-200g/mper coat.

 

New boards assuming I use OSB3 T&G. I'd need around 60 8'x2' sheets. 60 x £16.50 (Selco BM) = £990.00. Or non T&G 8'x4' sheets at £21.00 ea so £630.00 (£2500.00 in marine ply).

 

Insulation if I went PIR. Say 30 sheets of 150mm at £60 so around £2000.00. Something like this detail:

 

des_001.thumb.JPG.db1b9779cba185e25ea7f41fe9e99b7e.JPG

 

GRP trims, corners etc, guessing maybe £250 - 300.

 

Facias, soffits, new guttering.....

 

I reckon I could be looking at around £5K to do this "properly". Looks like it'll be that sheet of DPM and some bags of sand then for now! ? It's my dream to be able to not worry about the cost of things and do it the best I can. I could do wonderful things. Oh well, should have done better at school! PV is even further off than redoing the roof! 

 

Just ran the sizes through some handy calculators on Rubber4Roofs. EPDM then polyurethane liquid:

 

r4r_001.JPG.f7819ef67b39bf691ada20ce56978e8c.JPG

 

r4r_002.JPG.32be28f16d9dcc4b0c597d4ec2ebb4c9.JPG

 

Just putting off getting up on the roof by doing some CAD for the Makita battery to B&Q "Performance" 18V hedge trimmer, Li-ion conversion. That and SWMBO and the kids are still in bed after a really late night! The bedrooms are below the dormer roof. 

 

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3 minutes ago, SteamyTea said:

Had a girlfriend called Ruth.

 

Off to buy some new underwear at touchingcloth.com.

 

Touch n Go, shampoo for the terminally ill!

 

Gotta love Viz!

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The top layer of green mineral just peeled off the.....green mineral underneath. WTF do it like that?

 

20200613_142115

 

Quick video after peeling all the loose stuff off and launching it into the front garden:

 

Temporary repair whilst I gather my thoughts! ?

 

20200613_145209

 

I must have cut that DPM for some reason...it was wider when I used it the other side...

 

I'll add some more weight tomorrow.

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@Onoff, the weather's with you for a good while now. Crack on!

Quote

Sunday 28 Jun - Sunday 12 Jul
Probably remaining fairly unsettled during the latter part of June with showers or longer spells of rain, these turning heavy and possibly thundery across the south. Despite the mixed conditions, all parts should still see some drier and brighter interludes. Temperatures should generally be above average, possibly turning very warm in places. Around the turn of the month and into early July, a transition to more settled conditions is signalled with many seeing more prolonged drier and sunnier spells. However, there is still the chance of showers for most at times. Temperatures likely to return back to around average.

Updated: 04:00 (UTC+1) on Sun 14 Jun 2020

https://www.metoffice.gov.uk/

 

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  • 3 years later...

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