• We invite you to join UKWorkshop.
    Members can turn off viewing Ads!

Detached garage modernisation/conversion advice

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

Persephone

Established Member
Joined
23 Jun 2021
Messages
44
Reaction score
18
Location
North West
Hello everyone,
We are in the process of buying our first house. It is a small semi built in 1939. The same family lived there for 60+ years so it needs updating - rewire, central heating, etc. but it's got lots of potential.
I currently do hobby woodworking in my living room as I live in a rented apartment so I want a workshop. The house has a detached garage (approximately 18' by 8') built from preformed concrete with a cement roof in the 1960s. It looks solid but has not been cared for and the owners seem to have grown bramble bushes on the roof. At some point electricity was added. This runs from the consumer unit through an isolation switch into trunking that runs along the outside wall of the house and then spans a gap of approximately six feet to the garage. The trunking is damaged at this span exposing the twin and earth cable. In the garage cables feed three lights and several double sockets. Bare cables are tacket to the walls.
I have attached some photos but these are poor quality as I took them at the viewing.

I would be grateful of members' advice on whether I can modernise this garage to convert it to a workshop. At the moment I have a couple of questions around the structure and electrics.
I am thinking of insulating the walls, floor and roof with PIR around 60mm thick. Do I first need to cover all the interior surfaces with some sort of plastic water barrier? There is evidence of moisture seeping in through the walls where the garage runs alongside a concrete path that rises towards the rear of the garden. Should I coat these surfaces in some sort of oil based water repellent before the insulation goes on?
Do I need to leave a gap between the roof and the insulation?
I will then put a vapour barrier on the inside of the insulation and attach 18mm MDF sheets to the walls and roof. I'm going with MDF as it's dense and apparently better at reducing noise than OSB. For the floor I'll put down a vapour barrier then 18mm plywood.
I will also insulate the doors.
Does all of this seem like the right thing to do to make the structure useable as a workshop that's so close to the house (and neighbours)?
At present I am not sure if the garage has a consumer unit. I would like to fit one and run a 32 amp ring for sockets, a separate 16 amp radial for a 16 amp socket (I've been watching Laura Kampf and would like to have a go at welding) and a 6 amp radial for the lights. I would also like to replace the cable from the house consumer unit with an AWS cable and catenary wire.
I have purchased several LED lighting panels and dimmer switches from B&Q to replace the current strip lights. I will run the t&e for all wires on the surface using trunking.
My question here is whether I am allowed to do this myself? I am not an electrician though I do have a science background. As the infrastructure is already in place and I am replacing it because it is damaged is this notifiable work?

You might wonder why I am focusing on the garage rather than the house. Over the past few months I've acquired various pieces of workshop machinery (currently cluttering up my parents' house) and plan to use the workshop to do much of the house modernisation. The house will get a full rewire at some point but I want to get the workshop up and running straight away.

Anyway, for people who got this far on my lengthy post I'd be very grateful of your advice.

Thank you,
Steff
 

Attachments

Jameshow

Established Member
Joined
4 Oct 2020
Messages
1,875
Reaction score
890
Location
Bradford
I would put 25mm pir in between the posts and 25mm over the top thus reducing the space it takes up!

I'd put insulation under the floor too.

I'd buy OSB / MDF or ply - whatever is cheapest.

I'd batten the roof steels and put 2" pir fitted tightly between with 9mm OSB or ply over the top.

Cheers James
 

robgul

Barry Bucknell is my hero
Joined
13 Feb 2020
Messages
712
Reaction score
412
Location
Stratford-upon-Avon
You probably don't want to hear this . . .

You are looking, from your description, at spending quite a bit on materials to patch up a concrete garage which - from the pictures - is already crumbling (the reinforcing steel rusts and pops the concrete).

I would suggest that for not a lot more money - but yes probably more time - you would be better of building a new garage from scratch on the existing concrete base. Timber frame, cladding and insulation etc. My reasoning is really based on the longevity of the building even with the insulation/cladding etc that you describe.

Sorry!
 

Fitzroy

All the gear...
Joined
12 Mar 2013
Messages
1,740
Reaction score
793
Location
Aberdeen
If you’re into the house for a decent run 5+ Yrs i’d knock it down and start over. If not I’d get a warm sweater and a fan heater and repair any leaks.
 

eribaMotters

Established Member
Joined
12 Feb 2010
Messages
486
Reaction score
194
Location
Formby, Merseyside
I agree with above posts. The garage has reached a point where you are best to replace it. I noticed in first photo a patio across the bottom of the garden. Could you use the present garage for storage whilst building something new across the patio area. You'd have the added advantage of blocking out the view into/out of the windows on the housed behind you.

Colin
 

Sachakins

The most wasted of days is one without woodwork
Joined
4 Apr 2020
Messages
890
Reaction score
557
Location
Liverpool
A fresh start will be cheaper in the long run. Trying to get what you want constrained by what's already there will be an expensive retro fit!

Sorry for the pessimism, but I would rip it down and build something to meet your needs, rather than try and salvage what's there as it looks beyond simple upgrade and to far gone already.
 

Bristol_Rob

Established Member
Joined
18 Jul 2018
Messages
286
Reaction score
139
Location
Bristol
Damaged garages are like damaged relationships - sometimes you just need to start over ;)
 

Persephone

Established Member
Joined
23 Jun 2021
Messages
44
Reaction score
18
Location
North West
I would put 25mm pir in between the posts and 25mm over the top thus reducing the space it takes up!

I'd put insulation under the floor too.

I'd buy OSB / MDF or ply - whatever is cheapest.

I'd batten the roof steels and put 2" pir fitted tightly between with 9mm OSB or ply over the top.

Cheers James
Thanks James. Good idea about the PIR between the posts. Hadn't thought about battens for the roof but it makes sense. Though having looked at the comments below I think the general consensus is to get the dynamite out! 😄
 

Persephone

Established Member
Joined
23 Jun 2021
Messages
44
Reaction score
18
Location
North West
You probably don't want to hear this . . .

You are looking, from your description, at spending quite a bit on materials to patch up a concrete garage which - from the pictures - is already crumbling (the reinforcing steel rusts and pops the concrete).

I would suggest that for not a lot more money - but yes probably more time - you would be better of building a new garage from scratch on the existing concrete base. Timber frame, cladding and insulation etc. My reasoning is really based on the longevity of the building even with the insulation/cladding etc that you describe.

Sorry!
Haha nothing to be sorry about. We tried to buy this house in February but couldn't reach an agreement on price given the work needed and back then my thought was to demolish it and build a new workshop from wood. Now two other attempted purchases later and the opportunity to buy this for less and I will probably do that. I'll use this garage in the meantime without improvement to fix up the house. 😊
 
Last edited:

Persephone

Established Member
Joined
23 Jun 2021
Messages
44
Reaction score
18
Location
North West
If you’re into the house for a decent run 5+ Yrs i’d knock it down and start over. If not I’d get a warm sweater and a fan heater and repair any leaks.
Yes we plan to live there for many years so I'll probably take you advice and use a heater until I can build a new one. 😊
 

Persephone

Established Member
Joined
23 Jun 2021
Messages
44
Reaction score
18
Location
North West
I agree with above posts. The garage has reached a point where you are best to replace it. I noticed in first photo a patio across the bottom of the garden. Could you use the present garage for storage whilst building something new across the patio area. You'd have the added advantage of blocking out the view into/out of the windows on the housed behind you.

Colin
Thanks Colin, I had considered using the back of the garden but it's a raised area and I'd have to carry everything up those steps. But I agree with most people and think the garage needs to be replaced. I'll use it for the renovation as it is. 😊
 

Persephone

Established Member
Joined
23 Jun 2021
Messages
44
Reaction score
18
Location
North West
A fresh start will be cheaper in the long run. Trying to get what you want constrained by what's already there will be an expensive retro fit!

Sorry for the pessimism, but I would rip it down and build something to meet your needs, rather than try and salvage what's there as it looks beyond simple upgrade and to far gone already.
I agree with you. I might be able to make use of the area behind it too if I start over. 😊
 

Jameshow

Established Member
Joined
4 Oct 2020
Messages
1,875
Reaction score
890
Location
Bradford
How about building a stud wall inside the garage complete with vapour barrier then when you have the time you can dynamite the garage leaving the stud walls ready to be clad on the concrete + brick base...
 

RichardG

If at first you don’t succeed have a cup of tea.
Joined
29 Mar 2018
Messages
733
Reaction score
373
Location
South Norfolk
Looking at the picture it appears that no guttering is used on either yours or the neighbouring garage so the gap between the two must get completely saturated when it rains, I'm not surprised there's water coming under the wall. If you use it in it's current state then I would try and at least address that otherwise it will always be damp. Trouble is it involves the neighbour which can extremely variable....
 

ekynoxe

Member
Joined
30 Dec 2021
Messages
5
Reaction score
0
Location
Guildford
OMG! @Persephone I've got the exact same garage which is in the same state, including the ivy crawling on top and lifting the roof! Striking similarity!!
The damp is so bad that it's growing fungus and a lot of my boards are rotting because of it!

I've sealed all the joints between the slabs with expanding foam as temporary measure against too much water coming for for now, and I've replaced the roof a couple of years ago. I also added gutters before last winter and it did help a little bit, but I know full well that the time has come to do something about the whole thing.
As others said: don't waste any time or money on it!!

Whilst it's empty, bite the bullet now and replace it. I wish I did that first thing when I moved in...

My next large project will be to demolish it entirely and start from scratch with a properly tanked slab and footings, make it longer and insulate it.
 

ekynoxe

Member
Joined
30 Dec 2021
Messages
5
Reaction score
0
Location
Guildford
Actually, you're luckier than I am. Mine doesn't even have a slab underneath. It's just some sort of screed that I can chip away at, and it's not levelled.
If the slab is in good condition, I'd waste no time in your case and flatten the area for a fresh rebuild.
 

Dynamite

Established Member
Joined
23 Oct 2021
Messages
109
Reaction score
83
Location
Hull, England, UK
You probably don't want to hear this . . .

You are looking, from your description, at spending quite a bit on materials to patch up a concrete garage which - from the pictures - is already crumbling (the reinforcing steel rusts and pops the concrete).

I would suggest that for not a lot more money - but yes probably more time - you would be better of building a new garage from scratch on the existing concrete base. Timber frame, cladding and insulation etc. My reasoning is really based on the longevity of the building even with the insulation/cladding etc that you describe.

Sorry!
+1 for new, it will end up like triggers sweeping brush if it doesnt fall down first. It would be a nightmare to get it done up after all that hard work and still be in a position where its not stable.

Rob
 

Latest posts

Top