Block Built Outbuilding Advice

[djdk]

Hi,

We've recently moved into a new house which has a block built outbuilding/shed at the bottom of the garden, about 4m x 4m big. Its got a PVC door and a single PVC double glazed window and a flat felt roof.

Its currently used for a bit of storage (ok, a lot of storage) and is fine for that but I'd really like to use it as a studio/music room and it really needs some finishing off to make it suitable. When we first viewed the house in January it was really quite cold in there, and it smells a bit damp with an area of damp on one of the walls. I'm pretty much a novice DIYer and was hoping I might be able to pick some peoples brains as to what to do...

The front wall is brick, but the other 3 are exposed breeze blocks. The pointing in places in definitely a bit shoddy.

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• djdk
• 28 May 2014
• 1

Untitled

• djdk
• 28 May 2014
• 1

The damp on the inside seems to correspond with a hole where the power cable enters...

Untitled

• djdk
• 28 May 2014
• 1

Untitled

• djdk
• 28 May 2014
• 1

The floor is solid concrete and the rest of the walls seem to be plasterboard attached to the walls with some kind of gap, although im yet to really pull anything off to have a proper look. I cant see any evidence of a DPC and theres no ventilation (air brick etc).

My thoughts are that Im going to need to do something with the external walls. I was initially thinking of cladding it somehow but this seems rather expensive, especially seeing as the three exposed block walls arent really seen. Would painting be enough? Sealing the cable entry hole with expanding foam and covering I will definitely do.

The roof seems to be OK but doesnt really have an overhang on either side, is this something that might cause problems down the line? I'd rather do the thing properly once!

For the inside walls I was anticipating taking off the existing plasterboard and fitting new stuff with 50-75mm of insulation behind with a moisture proof membrane between the block work and the insulation.

Will the floor need some kind of insulation as well? I was planning on putting a cheap hard wearing carpet down.

Sorry for all the questions, I've been trying to research this as much as I can on my own but have got to the point where I need to ask people rather than google! My budget is £1K to £1.5K, I'd really like to do as much of this myself as possible as its a good opportunity to gain some life skills, but I wont be offended if anyone suggests that I might need a pro!

 

[jeds]

Given the internal is boarded and the external is pretty poor I would lean towards external insulation and cladding. Like a rendalath type system but you could make up your own from cheap seconds insulation panels and expamet. The floor really needs insulation as well. something like 40mm insulation with 22mm moisture resistant flooring would do.

 

[LegoLayer]

render the outside,,easy job

just get a bag of rendering sand and a few bags of cement,,few corner beads and away you go

strip the inside out,,battern it out and use insulated plasterboard,,,few bags of plaster,,,done

screed and tile the floor with a little insulation underneath,,,,easy


your budget is alot for the above work on a 4m x 4m outhouse,,,,,,so you could easy fit a log burner,new lights and buy all the tools to do the job,,,and have change left over

 

[noseall]

The black spot mold is indicative of cold bridging and is a typical symptom of the lack of insulation.

The metal back box and possibly metal capping are where the internal moisture is condensing.

As Jeds said, you need insulation to protect from the cold.

£1000 - £1500 is not a big budget for a 16m² space so spend wisely.

Lego Layer - stick to site-work bud, you ain't got a clue.

 

[LegoLayer]

The black spot mold is indicative of cold bridging and is a typical symptom of the lack of insulation.

The metal back box and possibly metal capping are where the internal moisture is condensing.

As Jeds said, you need insulation to protect from the cold.

£1000 - £1500 is not a big budget for a 16m² space so spend wisely.

Lego Layer - stick to site-work bud, you ain't got a clue.

funny that mate,,,,ive just built a 28m2 block garage in my garden for less than £1500,,,,and thats buying new materials from travis perkins

i have got a clue my friend,,,,,,,i dont charge the earth for my work like some

i could list my materials out with prices if you like??????

 

[noseall]

funny that mate,,,,ive just built a 28m2 block garage in my garden for less than £1500,,,,and thats buying new materials from travis perkins

What are the dimensions of this garage?

What was the cost of digging the foundations and getting rid of the spoil, labour and materials?

What was the cost of the concrete and how much did you put in? How much did it cost to lay? Did you mix yourself?

How much did it cost in labour and materials to cast the floor slab? did you use a polythene dpm? Reinforcing?

How many block courses were there below ground?

Does the garage have a personnel door as well as a garage door?
Are there any windows?

How much did these doors and windows cost?

Were there any pillars in the garage?

How many courses up to wall plate?

How is the roof strapped down, i.e. have you used a standard wall plate with bent straps?

Does this garage have a pitched roof or a flat roof? If pitched was it cut roof or trusses?

If flat how was it finished and how much did it cost?

If pitched how was it finished and how much did it cost?

How is the soffit/fascia/gutter detail finished off?

How is the rainwater dealt with i.e. drains etc?

How is the inside finished?

Is the ceiling plastered?

Are there any electrics in the garage?

Is the garage insulated?

How much have you allowed overall for labour?

 

[wakey77]

funny that mate,,,,ive just built a 28m2 block garage in my garden for less than £1500,,,,and thats buying new materials from travis perkins

What are the dimensions of this garage?

What was the cost of digging the foundations and getting rid of the spoil, labour and materials?

What was the cost of the concrete and how much did you put in? How much did it cost to lay? Did you mix yourself?

How much did it cost in labour and materials to cast the floor slab? did you use a polythene dpm? Reinforcing?
Jesus you must be getting some discount on those materials mate I avoid Travis like the plague.
How many block courses were there below ground?

Does the garage have a personnel door as well as a garage door?
Are there any windows?

How much did these doors and windows cost?

Were there any pillars in the garage?

How many courses up to wall plate?

How is the roof strapped down, i.e. have you used a standard wall plate with bent straps?

Does this garage have a pitched roof or a flat roof? If pitched was it cut roof or trusses?

If flat how was it finished and how much did it cost?

If pitched how was it finished and how much did it cost?

How is the soffit/fascia/gutter detail finished off?

How is the rainwater dealt with i.e. drains etc?

How is the inside finished?

Is the ceiling plastered?

Are there any electrics in the garage?

Is the garage insulated?

How much have you allowed overall for labour?

 

[wakey77]

funny that mate,,,,ive just built a 28m2 block garage in my garden for less than £1500,,,,and thats buying new materials from travis perkins

What are the dimensions of this garage?

What was the cost of digging the foundations and getting rid of the spoil, labour and materials?

What was the cost of the concrete and how much did you put in? How much did it cost to lay? Did you mix yourself?

How much did it cost in labour and materials to cast the floor slab? did you use a polythene dpm? Reinforcing?
Jesus you must be getting some discount on those materials mate I avoid Travis like the plague.
How many block courses were there below ground?

Does the garage have a personnel door as well as a garage door?
Are there any windows?

How much did these doors and windows cost?

Were there any pillars in the garage?

How many courses up to wall plate?

How is the roof strapped down, i.e. have you used a standard wall plate with bent straps?

Does this garage have a pitched roof or a flat roof? If pitched was it cut roof or trusses?

If flat how was it finished and how much did it cost?

If pitched how was it finished and how much did it cost?

How is the soffit/fascia/gutter detail finished off?

How is the rainwater dealt with i.e. drains etc?

How is the inside finished?

Is the ceiling plastered?

Are there any electrics in the garage?

Is the garage insulated?

How much have you allowed overall for labour?

 

[ban-all-sheds]

funny that mate,,,,ive just built a 28m2 block garage in my garden for less than £1500,,,,and thats buying new materials from travis perkins

What are the dimensions of this garage?

What was the cost of digging the foundations and getting rid of the spoil, labour and materials?

What was the cost of the concrete and how much did you put in? How much did it cost to lay? Did you mix yourself?

How much did it cost in labour and materials to cast the floor slab? did you use a polythene dpm? Reinforcing?
Jesus you must be getting some discount on those materials mate I avoid Travis like the plague.
How many block courses were there below ground?

Does the garage have a personnel door as well as a garage door?
Are there any windows?

How much did these doors and windows cost?

Were there any pillars in the garage?

How many courses up to wall plate?

How is the roof strapped down, i.e. have you used a standard wall plate with bent straps?

Does this garage have a pitched roof or a flat roof? If pitched was it cut roof or trusses?

If flat how was it finished and how much did it cost?

If pitched how was it finished and how much did it cost?

How is the soffit/fascia/gutter detail finished off?

How is the rainwater dealt with i.e. drains etc?

How is the inside finished?

Is the ceiling plastered?

Are there any electrics in the garage?

Is the garage insulated?

How much have you allowed overall for labour?

But he didn't.

 

[djdk]

Well that got out of hand quickly!

Given the internal is boarded and the external is pretty poor I would lean towards external insulation and cladding. Like a rendalath type system but you could make up your own from cheap seconds insulation panels and expamet. The floor really needs insulation as well. something like 40mm insulation with 22mm moisture resistant flooring would do.

Thanks for the reply, what you say makes a lot of sense, I hadnt considered putting the insulation on the outside, are there any downsides to that approach? Currently the roof felt just drops down the side of the wall, I guess that will need some attention? Theres also the front wall which is brick that I wasn't going to touch if insulating inside, is there anything wrong with insulating that wall on the inside and doing the others externally?

 

[jeds]

Well that got out of hand quickly!

Given the internal is boarded and the external is pretty poor I would lean towards external insulation and cladding. Like a rendalath type system but you could make up your own from cheap seconds insulation panels and expamet. The floor really needs insulation as well. something like 40mm insulation with 22mm moisture resistant flooring would do.

Thanks for the reply, what you say makes a lot of sense, I hadnt considered putting the insulation on the outside, are there any downsides to that approach? Currently the roof felt just drops down the side of the wall, I guess that will need some attention? Theres also the front wall which is brick that I wasn't going to touch if insulating inside, is there anything wrong with insulating that wall on the inside and doing the others externally?

The only issue with external insulation really is the potential for impact damage and whether there is enough roof overhang to accommodate the extra thickness. But do all internal or all external. It doesn't really work to change half way around because of cold bridging issues. Having a good brick face worth keeping alters the balance slightly. For me it would probably come down to the current condition of the internal. If it's in really good nick it would be a shame to tear it out just to replace it - especially when the external is so rough and needs some sort of finish anyway. If the internal is a bit ropey and could do with tidying up I'd probably go internal and just render the three sides externally. Obviously the roof eaves will need attention.

 

[ban-all-sheds]

I hadnt considered putting the insulation on the outside,

http://www.google.co.uk/search?q=external+wall+insulation

are there any downsides to that approach?

Provision of mechanical protection - when houses are done they usually fix a mesh over the insulation and then render it. For your outbuilding timber cladding might be an option.

Replacing windowsills or installing oversills.

Roof overhang.

Upsides include no worries about a vapour control layer inside, or condensation on the walls, greater temperature stability because of the thermal mass of the walls, and (often of great utility in an outbuilding), freedom to screw any fixings anywhere on the walls inside.

 

[LegoLayer]

i sense abit of 'know it all' behaviour in the above posts regarding my 28m2 garage

heres a few answers/info for anyone interested,,,,,iam sure the 'pro's above will have a good time picking out and try there hardest to hammer me down,,,,,but the fact is ive done it and do it every year


6m x 4.7m,,,,,keeping it under 30m2

10 tonne ballast,,footings/floor,,,,,,,£250

8 packs of concrete 4 inch blocks,,,,,,,£480,,,,,,,72 in a pack=576

2 tonne of building sand,,,,,,,,,,,,,,,,,,,£50

cement,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,£150

3m door lintel,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,£120

2 x 4.5m steel beams,,,,,,,,,,,,,,,,,,,,,,,£100

scaffold board garage door,,,,,,,,,,,,,,,£100

roof

5 x 6x2 6m

10 x 1220x2440 18mm osb,,,,,,,,,,,,,,,,,£280

bitumen/felt,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,£150




labour is free,,,,,,feb mix is free,,,,,nails are free,,,,,everything was mixed in a wheel barrow,even the concrete!!!!lol

i dont touch electrics but its only £200 to get my garage kitted out with fluorescents,,,,going in next week

i little over but still way under £2000,,,,,,,,,,,,done,,,lol



i pulled a single garage down for a customer the other week,,,,,,,,this garage was built on a 2 inch concrete slab,,,no dpm,,,,had been sat there for 30 years and it still looked perfect,,,,i asked about damp and he said its been dry as a bone,,,,lucky but it makes you wonder

ive demolished plenty of outbuildings over the years,,,,some people like the snobs above just dont understand that old methods still work and do the job just as good

 

[noseall]

i sense abit of 'know it all' behaviour in the above posts regarding my 28m2 garage

Not really no.

Just that your post about building a garage for £1500 was misleading and the above post has proved me right.

I especially love the bit about a scaffold board garage door!

 

[ban-all-sheds]

funny that mate,,,,ive just built a 28m2 block garage in my garden for less than £1500

the fact is ive done it and do it every year

Do you build one garage a year because each one only lasts that long?