# Garage refurb project - advice sought



## newfhouse (12 Sep 2021)

I have a tired old prefab detached garage that I need to fix up. It’s made of concrete panels slotted into concrete verticals with a bonded asbestos sheet roof to the rear and a short but steeper tiled front. I live on a slope so the rear of the garage is effectively buried the best part of a metre deep. It measures 5.9 m x 2.8 m.

The metal frame that held the bottom square has completely rotted away but nothing moves and I’m pretty confident it won’t. The steel frame that holds the roof up is surface rusty but not rotten so I expect I should be able to brush the worst off and Hammerite it.

I’m comfortable with removing the existing roof sheets and wrapping them for the council to take away. They should come off whole despite there being lengthwise cracks in a couple.

There are two windows, both rotten, and a wooden side door which is disintegrating from the bottom up. I’ve thought about replacing the windows if I can find suitable cheap replacements of the correct size to slot in. I’m less bothered about the side door and thinking of filling the gap with concrete panels. First question: does anyone know where I might be able to buy replacements? They are shaped to overlap top and bottom. I thought of buying concrete gravel boards and cutting to size but I don’t think I’m sufficiently skilled with a grinder to make a good job of the overlap.

The next question is about the roof. As I see it I could board it and then felt it, board and bitumen sheet, or use plastic coated corrugated steel sheet, with or without a board underneath. I should say that it would be useful to be able to walk on the roof when complete as I need to be able to cut back trees and ivy that are otherwise inaccessible. I’ve not used the steel sheet before. I see it comes in different gauges but is there anything I need to know? I intend to retile the front part of the roof, but I’m not sure how best to fix the ridge tiles at the transition from front to rear.

I’m not looking to spend a fortune on this but I do need it to be waterproof and look presentable. I had a quote of £2500 from a local builder which doesn’t feel like value for money as I could get a new prefab garage installed for not much more. If I could do the job myself with reasonable but not stellar DIY skills for less than £1000 I would be happy.

What does Team CC think?


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## Archie_tect (12 Sep 2021)

When you say it is retaining up to a metre of ground... anything over 600mm [edit!] difference in level requires an engineered retaining wall... be very careful if the frame has rotted - what's holding the concrete panels in place? Might need a structural engineer to give you some advice [is there one on CC?]

The roof is the least of your worries, unless it is genuinely asbestos sheeting... in which case the Council will need to know before they collect it as disposing of it properly normally gets charged for.

Photos would help.


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## bruce1530 (12 Sep 2021)

Asbestos - depends where you live. My own council have a "catch 22" system for disposal of "domestic" (ie non-trade) asbestos cement sheet. No charge. They won't uplift, but f it's double-bagged, they'll accept it at the main waste site and put it in the asbestos skip. 
However, they also say that, while they'll accept domestic asbestos, you're not allowed to transport it there unless you're a licensed waste carrier. And that make it non-domestic..... :-)

In practice, I took some asbestos flue pipe there a few months ago, double bagged, no problem - the guy couldn't have been more helpful.


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## newfhouse (12 Sep 2021)

Archie_tect said:


> When you say it is retaining up to a metre of ground... anything over 650mm difference in level requires an engineered retaining wall... be very careful if the frame has rotted - what's holding the concrete panels in place?


I will have a proper measure tomorrow. It’s been there a long time and doesn’t look like it’s going anywhere.



Archie_tect said:


> asbestos sheeting... in which case the Council will need to know before they collect it as disposing of it properly normally gets charged for.





bruce1530 said:


> Asbestos - depends where you live.


My understanding is that the Corporation of London deals with hazardous waste for most of the London boroughs and will collect domestic quantities of asbestos cement sheets if double bagged.
https://www.croydon.gov.uk/sites/default/files/Asbestos-information2017.pdf



Archie_tect said:


> Photos would help.


I will post some tomorrow.


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## Archie_tect (12 Sep 2021)

That's an incredibly generous service that London Boroughs provide and even more incredible that it's totally free to collect up to 15sq metres of asbestos sheeting!


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## newfhouse (12 Sep 2021)

Archie_tect said:


> That's an incredibly generous service that London Boroughs provide and even more incredible that it's totally free to collect up to 15sq metres of asbestos sheeting!


Not really free if you saw my council tax bill, but welcome nevertheless. I guess they think it’s cheaper than clearing up fly tipping of such material.


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## Drago (13 Sep 2021)

I'd be inclined to steer clear of bitumen sheet. In my experience it sags over a couple of years, no matter how many beams and purlins support it from below.

Box section galv steel is more expensive but is solid as a rock once fitted. I can highly recommend... www.cladco.co.uk

It cost me just under £500 for the 0.7mm box section sheet to do my 18 foot garage.

Good luck.


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## the snail (13 Sep 2021)

I agree with drago, used steel for my shed, probaby you can reuse the supports from the cement roof, and it's quick and easy to install. I used the plastic coated sheets, still looks good as new. You'd have to use crawler boards to walk on it though.


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## MichaelW2 (13 Sep 2021)

Whenever I remove suspected asbestos I spray with diluted PVA to reduce dust. Use a quality mask and disposable overalls. 
It wont hurt to do removal on a rainy day.

Are the wall concrete panels loaded with asbestos?


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## newfhouse (13 Sep 2021)

MichaelW2 said:


> Are the wall concrete panels loaded with asbestos?


I don’t know. I wasn’t planning to disturb them too much.


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## newfhouse (13 Sep 2021)

Drago said:


> Box section galv steel is more expensive but is solid as a rock once fitted. I can highly recommend... www.cladco.co.uk


Thanks, that looks good.



the snail said:


> I agree with drago, used steel for my shed, probaby you can reuse the supports from the cement roof, and it's quick and easy to install. I used the plastic coated sheets, still looks good as new. You'd have to use crawler boards to walk on it though.


I hope I can just drill and screw the sheets to the existing roof frame. Not sure if I need to use a timber batten between the new and the old metal. Point taken about using crawler boards, that would still allow access. The frame members are 33“ / 84 cm apart.

How is a metal roof with condensation? Does it need an underfelt?


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## newfhouse (13 Sep 2021)

Archie_tect said:


> When you say it is retaining up to a metre of ground... anything over 600mm [edit!] difference in level requires an engineered retaining wall...


Its not as much as I thought, about 700 mm. I’m going to leave it as is, I think.



Archie_tect said:


> Photos would help.


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## Drago (13 Sep 2021)

newfhouse said:


> Thanks, that looks good.
> 
> 
> I hope I can just drill and screw the sheets to the existing roof frame. Not sure if I need to use a timber batten between the new and the old metal. Point taken about using crawler boards, that would still allow access. The frame members are 33“ / 84 cm apart.
> ...


That I don't know for sure. No condensation yet, but mine has only been up for the warmer months. I my case its a large, well ventilated area so im gooing my calculations are correct and won't have a problem, but you're wise to consider the matter.

You can pay an extra couple of quid and the sheets come with a dripstop backing.


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## jowwy (3 Oct 2021)

Hows this project coming along @newfhouse


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## newfhouse (3 Oct 2021)

jowwy said:


> Hows this project coming along @newfhouse


I think I've settled on how I'm going to do it and I'm about to order the materials. Annual leave is booked for two weeks time so weather permitting I'm hoping to make good progress then.

The renovation of the house itself is substantially complete now, externally at least. Scaffolding is coming down tomorrow if my less than reliable contractors turn up as promised.


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## battered (12 Oct 2021)

MichaelW2 said:


> Whenever I remove suspected asbestos I spray with diluted PVA to reduce dust. Use a quality mask and disposable overalls.
> It wont hurt to do removal on a rainy day.
> 
> Are the wall concrete panels loaded with asbestos?


One of the tricks used by contractors is to slather it in wallpaper paste. No dust then.


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## newfhouse (17 Oct 2021)

I started removing the roofing sheets today.







It looks like all six will come off whole which is a relief. I now have easier access to cut back all the ivy and other vegetation between my neighbour’s garage and mine. I wire brushed the roof support frame and have given the parts exposed so far a liberal coat of Hammerite.

I can’t fully remove the sheets until my unreliable scaffolders actually turn up to remove their kit which is in the way. But that’s another story…

The side door has never been usable and has sunk over time as it rotted from the bottom. I built a new door frame and ledge/brace tongue and groove door which is now primed for painting. New window frames will be fettled tomorrow but I won’t glaze them until the heavy work is finished. The prefab nature of the garage means I have an opportunity to reduce the size of the windows (for security) and add another one.

Tomorrow will hopefully also see me remove and rebuild the tiled front part of the roof.

I’m enjoying myself so far


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## battered (17 Oct 2021)

Most of those prefab garages have windows only 6" wide of so, smaller than a human head.


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## newfhouse (17 Oct 2021)

battered said:


> Most of those prefab garages have windows only 6" wide of so, smaller than a human head.


The original was a four pane job, about 30” square - three panels high. I’m probably going to reduced it to two panels high and add another one on the side.


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## newfhouse (24 Oct 2021)

Progress has been slower than I had anticipated. A colleague having a baby meant that I cancelled my leave last week to cover his night shift so I only had a few hours each day to get stuck in.





As I hoped, the roof panels came off whole and are now wrapped and awaiting collection tomorrow. The total size was a little over the allowable 15 m^2 - when I measured I forgot to include the overlap - so I had to pay an extra £8.58 .





All of the metal frame is sound apart from this one supporting the ridge, so I replaced that and painted the rest.





I built a treated timber frame to attach on top of the old metal, giving me something to fix the new roof panels to.





Windows resized and moved, new door painted.





Frame and battens fixed and a few tiles hung just to test. I need some more tiles but I’m currently struggling to find someone with stock that will sell me a small quantity of grey Redland 49s or similar rather than a pallet of 336.

Cladco will be delivering my new panels and fascias on Tuesday.

Last but not least, the up and over door mechanism has finally given up. The top of the frame was already about to give way, repaired with a length of steel angle, but now the springs and runners and the lift arm on one side have disintegrated too. Probably time for a new door if I can find one of the right size. Looking online I can’t find anything less than 6’ 6” tall but my aperture is only 6’. What about a roller door? I’m not sure if I have sufficient headroom for the mechanism under my sloping tiled section. Does anyone have any helpful thoughts or expertise?


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## Colin Grigson (24 Oct 2021)

You’re making a great job of that, nice to see


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## jowwy (24 Oct 2021)

newfhouse said:


> Progress has been slower than I had anticipated. A colleague having a baby meant that I cancelled my leave last week to cover his night shift so I only had a few hours each day to get stuck in.
> 
> View attachment 614873
> 
> ...


Build some wooden doors that open outwards


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## newfhouse (24 Oct 2021)

jowwy said:


> Build some wooden doors that open outwards


Yes, I have thought about that but I don’t know if my carpentry and joinery skills are good enough to build and hang big heavy doors.

I will probably remove the existing door first and see if I can find a way of repairing the frame and mechanism that doesn’t involve throwing good money after bad. After that I need a plan B.


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## jowwy (24 Oct 2021)

newfhouse said:


> Yes, I have thought about that but I don’t know if my carpentry and joinery skills are good enough to build and hang big heavy doors.
> 
> I will probably remove the existing door first and see if I can find a way of repairing the frame and mechanism that doesn’t involve throwing good money after bad. After that I need a plan B.


Im sure you can do it, just take your time, measure twice, cut once…….


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## newfhouse (26 Oct 2021)

Reasonably watertight again, if not finished. Excellent service from Cladco - thanks for the steer @Drago - who delivered late yesterday rather than this morning as expected. That left me a whole day to get all the panels fitted, the old tiles hung on the front, and a very temporary ridge to keep the rain out. The weekend should see the barges and gutters fitted before I install my new consumer unit and renew the electrics.


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## fossyant (26 Oct 2021)

Looks great


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