Garden room brick/block advice please

[Eclipse2026]

Greetings :
I am replacing an old asbestos garage with a garden room. The footprint is sizeable, between 35-40m2.
The builder quotes I received through FB and Bark were so varied, ranging from £35-72k. Even at the low end, it is over my budget.
I decided I would hire each trade individually and cut out the middle man and source some of the materials myself.

My dad was a sparky and I lost him last year. Whilst a sparky, he would turn his hand to lots of things at home and was my go to person for everything, I am a pen pusher and miss him. I am hoping for some guidance as to what stages I should be doing things and some recommendations on the build.
It will be used for storage and a home office. Electricity, no plumbing.

I hired a digger who has demolished what was there and he will move on to the next stages :
Footings 450mm x 450 deep & wide
Solid floor / type 1 hardcore + 150mm concrete with mesh + 50mm screed

The next step is block & brick, I think some form of insulation between the two?
If the height is 2.5m, width 7m and depth 6m, how many engineered bricks do I need, normal bricks and blocks?
The guy who is doing my foundations initially told me he has a couple of bricky friends and it would cost £80m2, it then became £120m2 and would take 2
months to build because brickies can only lay a certain number of courses for stability or it would collapse. I Googled this and accept it is now winter, but 2 metres at a time seemed acceptable? Since the height is only 2.5 metres, I am confused.

Do I engage a roofer at the same time as a bricklayer or once the walls are complete or nearly complete, I am not sure if technically, they somehow work in unison?
The door/window fitter, is this something the bricklayer would do?

I am going for a flat roof, what sort of wooden beams do I need?
EPDM, GRP or felt roofing and what is involved and what sort of materials should I be looking at sourcing?

Attached is an AI generated photo of what I would like to achieve.

Appreciate some guidance. I am not cheap, but my funds are limited so I am trying to get a good build for a fair price.
Many thanks in advance.

 

[23vc]

Why not timber frame it like the vast majority of these are? Easier, probably cheaper, lose less space than a cavity wall. 450mm may not be deep enough for your footings depending on ground. Assume given the size it’s subject to building regs? In which case they’d inspect at various stages like when the footings are dug and they’d dictate the depth.
Rather than asking stuff like “how many bricks and blocks will I need” I’d focus on understanding what you’re trying to build enough to draw a fairly detailed plan of it. You’ll learn a lot in doing so and gain a better understanding of how the various trades come into it. You could engage an architectural technician, give them a brief of what you want and get them to do plans. Things like the 2.5m height rule, if you’re near a boundary, are critical and need planning right at the start.

 

[Eclipse2026]

30m2 is permitted development and I am winging it for the additional 5 or so since neighbours have larger, one with kitchen and bathroom and no planning permission and the property has since been sold, so assume the buyers' solicitors had no issue or obtained a certificate of lawfulness after the fact. 2.5m height is within permitted development. If I wanted timber or a flat pack, I wouldn't be asking here. You weren't able to answer the question, thanks for the effort.

 

[23vc]

Crikey - good luck fella

 

[noseall]

Greetings :
I am replacing an old asbestos garage with a garden room. The footprint is sizeable, between 35-40m2.
The builder quotes I received through FB and Bark were so varied, ranging from £35-72k. Even at the low end, it is over my budget.
I decided I would hire each trade individually and cut out the middle man and source some of the materials myself.

My dad was a sparky and I lost him last year. Whilst a sparky, he would turn his hand to lots of things at home and was my go to person for everything, I am a pen pusher and miss him. I am hoping for some guidance as to what stages I should be doing things and some recommendations on the build.
It will be used for storage and a home office. Electricity, no plumbing.

I hired a digger who has demolished what was there and he will move on to the next stages :
Footings 450mm x 450 deep & wide
Solid floor / type 1 hardcore + 150mm concrete with mesh + 50mm screed

The next step is block & brick, I think some form of insulation between the two?
If the height is 2.5m, width 7m and depth 6m, how many engineered bricks do I need, normal bricks and blocks?
The guy who is doing my foundations initially told me he has a couple of bricky friends and it would cost £80m2, it then became £120m2 and would take 2
months to build because brickies can only lay a certain number of courses for stability or it would collapse. I Googled this and accept it is now winter, but 2 metres at a time seemed acceptable? Since the height is only 2.5 metres, I am confused.

Do I engage a roofer at the same time as a bricklayer or once the walls are complete or nearly complete, I am not sure if technically, they somehow work in unison?
The door/window fitter, is this something the bricklayer would do?

I am going for a flat roof, what sort of wooden beams do I need?
EPDM, GRP or felt roofing and what is involved and what sort of materials should I be looking at sourcing?

Attached is an AI generated photo of what I would like to achieve.

Appreciate some guidance. I am not cheap, but my funds are limited so I am trying to get a good build for a fair price.
Many thanks in advance.

You are not going to build a 40sq/m structure, of any quality for under £30k, no matter how hard you try. As said, it's also b'regs relevant. So whether you involve them or not means you have to at least try and adhere to the regs.

What you don't want to build is a mouldy wreck no one want to go inside.

 

[Eclipse2026]

The arrogance of the 2 responders is phenominal. Responding for the sake of responding - notching up points and rubbing your own ego's. Mind your own beeswax with regard to cost and whether I decide to apply for planning permission or decrease to 30m2, that was not the question ! Don't know the answer? Move onto a post and assist someone where you do can.

 

[23vc]

Wind up thread

 

[carlbidwell12]

Building a garden room with brick or block is a solid choice, but getting the insulation and damp-proofing right is key. Make sure you consider cavity insulation, vapour control, and how moisture will be managed between the blockwork and internal finishes.


Here’s a related discussion on insulating a single-skin brick room which has some great tips: https://www.diynot.com/diy/threads/property management-insulating-a-single-skin-brick-room.405349/

 

[Eclipse2026]

Building a garden room with brick or block is a solid choice, but getting the insulation and damp-proofing right is key. Make sure you consider cavity insulation, vapour control, and how moisture will be managed between the blockwork and internal finishes.


Here’s a related discussion on insulating a single-skin brick room which has some great tips: https://www.diynot.com/diy/threads/property management-insulating-a-single-skin-brick-room.405349/

Thank you ! At last, some advice I can use

 

[Ivor Windybottom]

I was going to build my cavity walled shed from brick/block but decided on brick/brick. The interior walls are a very light coloured brick that I got very cheap from the brickhunter website (leftovers from some newbuild estate). They cost about the same as block (6 bricks are the equivalent of one block), but they'll take more mortar and labour. However, they won't need painting (block is very dark), and the interior walls will be nice and smooth instead of a rough spider hotel.

Go for it. Brick is vastly superior to wood. You won't be going out with a brush and a bucket of creosote in a few years desperately trying to preserve a decaying wooden building as most will end up doing.

 

[Eclipse2026]

I was going to build my cavity walled shed from brick/block but decided on brick/brick. The interior walls are a very light coloured brick that I got very cheap from the brickhunter website (leftovers from some newbuild estate). They cost about the same as block (6 bricks are the equivalent of one block), but they'll take more mortar and labour. However, they won't need painting (block is very dark), and the interior walls will be nice and smooth instead of a rough spider hotel.

Go for it. Brick is vastly superior to wood. You won't be going out with a brush and a bucket of creosote in a few years desperately trying to preserve a decaying wooden building as most will end up doing.

Thank you. Similar to you, I do not want maintenance which is why I decided I did not want timber and the 'pre packed' garden rooms are expensive and we do not yet know the lonjevity of these structures since they are recent newcomers.
Thank you too for the tip regarding bricks. I will, eventually, post pre and post photos and the total cost.

 

[Ivor Windybottom]

Our previous wooden shed wasn't rotten, but the rats had chewed a hole through the floor and were having a lovely time in there.

You're heading the right way. A bigger upfront cost, but with a far better long-term result.

Keep us updated. Ignore some of the daft attitudes on here, it's a lively forum!

 

[johnwilliam135]

Greetings :
I am replacing an old asbestos garage with a garden room. The footprint is sizeable, between 35-40m2.
The builder quotes I received through FB and Bark were so varied, ranging from £35-72k. Even at the low end, it is over my budget.
I decided I would hire each trade individually and cut out the middle man and source some of the materials myself.

My dad was a sparky and I lost him last year. Whilst a sparky, he would turn his hand to lots of things at home and was my go to person for everything, I am a pen pusher and miss him. I am hoping for some guidance as to what stages I should be doing things and some recommendations on the build.
It will be used for storage and a home office. Electricity, no plumbing.

I hired a digger who has demolished what was there and he will move on to the next stages :
Footings 450mm x 450 deep & wide
Solid floor / type 1 hardcore + 150mm concrete with mesh + 50mm screed

The next step is block & brick, I think some form of insulation between the two?
If the height is 2.5m, width 7m and depth 6m, how many engineered bricks do I need, normal bricks and blocks?
The guy who is doing my foundations initially told me he has a couple of bricky friends and it would cost £80m2, it then became £120m2 and would take 2
months to build because brickies can only lay a certain number of courses for stability or it would collapse. I Googled this and accept it is now winter, but 2 metres at a time seemed acceptable? Since the height is only 2.5 metres, I am confused.

Do I engage a roofer at the same time as a bricklayer or once the walls are complete or nearly complete, I am not sure if technically, they somehow work in unison?
The door/window fitter, is this something the bricklayer would do?

I am going for a flat roof, what sort of wooden beams do I need?
EPDM, GRP or felt roofing and what is involved and what sort of materials should I be looking at sourcing?

Attached is an AI generated photo of what I would like to achieve.

Appreciate some guidance. I am not cheap, but my funds are limited so I am trying to get a good build for a fair price. Also, if anyone is managing rental or investment properties nearby, checking out company lets London might provide some useful context for managing properties efficiently.

Hi, it sounds like you’ve got a big project ahead! For the brick and block work, most builders do lay walls in stages to ensure stability, so 2 metres at a time is reasonable, especially in winter. For insulation, a cavity wall with insulation between the blocks and bricks usually works well. Roofers typically come in once the walls are nearly complete, and door/window fitters are usually separate trades some bricklayers can fit frames, but it depends on their skill. For a flat roof, timber beams sized for the span plus either EPDM or GRP waterproofing are common and durable; felt is cheaper but may need more maintenance. Sourcing materials yourself can save money, just make sure everything meets building regs. Good luck with your garden room sounds like it will be a great space!

 

[mrrusty]

You are not going to build a 40sq/m structure, of any quality for under £30k

maybe, if you do everything yourself. My 6.5 x 3.6 cost knocking on towards £20K in materials including decorations etc, all in. I used SIPs, and for a garden room cannot think of a better method - structural and insulation in a single panel. Thread here if you're interested https://community.screwfix.com/threads/garden-room.256842/

It's used every day as both wife and I work from home in it. Takes very little heating to keep warm even in the depths of winter. Has been 100% stable - the internal skimming has zero cracks, so in 2+ years so far nothing has moved a smidgen. SIP's are incredibly strong and rigid, and over a substantial timber subframe, I suspect you could jack it up at one end and it wouldn't break its back.

 

[23vc]

Hi, it sounds like you’ve got a big project ahead! For the brick and block work, most builders do lay walls in stages to ensure stability, so 2 metres at a time is reasonable, especially in winter. For insulation, a cavity wall with insulation between the blocks and bricks usually works well. Roofers typically come in once the walls are nearly complete, and door/window fitters are usually separate trades some bricklayers can fit frames, but it depends on their skill. For a flat roof, timber beams sized for the span plus either EPDM or GRP waterproofing are common and durable; felt is cheaper but may need more maintenance. Sourcing materials yourself can save money, just make sure everything meets building regs. Good luck with your garden room sounds like it will be a great space!

This one’s AI, if you look at its post in GD also. Joined the forum today. Mods, please delete…