Which construction method

[ESA]

Hi all,

Bit of a newbie to construction so need help deciding the best construction method.

I want to build an 8m x 8m games/lads room at the bottom of the garden. Have been looking into it for some time and recently got written confirmation that I don't need planning permission (reasons listed at end for those that are interested).

As I may spend more time there than in the main house, I want the building to be extremely well insulated and have electricity, telephone, water and drainage supplies all run from the main house.

Main house is rendred and pebbledashed but this building will be 30 metres away at the bottom of garden without any neighbouring building so no real need to harmonise.

What I can't decide is the cheapest and best way to build it. Options that I am aware of are: -

1. Concrete Block and breeze block with cavity wall insulation. Rendred and pebbledashed.
2. Timber frame and cladding and insulation in between.
3. Solid 225 mm block with battens and plasterboard with insulation in between. Possible finished with render - not exactly sure what this is but assuming it is placing the 225 blocks longways and having single skin wall.

A local bricklayer has quoted £1 per block and estimated approx 200 blocks (8 metres x 3 metres high x 4 walls) and materials cost of £1.60 per square metre.

All help appreciated.

ESA

Reasons for not requiring planning permission are: -

1. Not a residential building.
2. Building not cited closer to a public highway than main house.

 

[denso13]

Wow first off I don't know how a building that size doesn't need planning permission, and second it must surely need a building warrant. I've built houses smaller than that!

 

[noseall]

local authorities state that buildings above 30m2 require p.p. or so i thought.

if they let you get away with a building that size, and of the specifications you've stated, then good luck to ya'.

 

[makitaman]

Thats a pretty large building, I'm also amazed that you don't need planning permission. Where I live anything over 30sqm needs permission.

 

[bikerm4]

Think the bricky needs to re-assess how many blocks he will need.

 

[^woody^]

You need to decide on the design, as this can determine the most cost effective construction method.

In addition the proposal sounds like it will be classed as a habitable room and be over the threshold of 30m2, and thus will require building regulation approval - which again will affect the construction method.

Any nearby trees and ground conditions will determine foundation design, so you need to consider this.

You could build a brick or timber framed structure to make a dry and comfortable room, but you really need to give it more thought on design and costs.

BTW, I make it 960 blocks, minus your window and door openings. And blocks are about £6 per metre plus sand and cement to buy. Let me know where they sell them for £1.60 per m2

Don't use that bricky he can't count, or he has quoted on lego blocks

 

[Aqua]

over the threshold of 30m2, and thus will require building regulation approval - which again will affect the construction method.

Any nearby trees and ground conditions will determine foundation design, so you need to consider this.

Spot on woody.

I have just been through this lot myself, i reduced my proposed 9m x 4m garage to below 30m2 to become permitted development.

This was because of a neighbours weeping willow tree, the building regs guy told me if i wanted 9m x 4m the foundation near the tree would have to be........

Wait for it........

7 feet 9 inches deep yes thats 7 feet 9 inch.

So ESA check very carefully as to anything near by that might give you this sort of problem.

Basically below 30m2 you have no real problem, 30m2 or more and things change quickly.

 

[^woody^]

But have you considerd that the willow tree will now affect your shallower foundations?

Lets hope not, but sometimes the BCO can have your intrests at heart

 

[gangman]

Depending on the ground, trees may not make any difference. I've built a 10m x 6m garage with 100ft sycamores within 3ft of the foundations. My property sits on ballast, I had to dig down 1200mm into the ballast and the BCO accepted this as apparently tree roots don't go down into the ballast.

My construction method was 100mm conc. block internal, 4x2 framework cladded with 6in featheredge sitting on facebrick panels for the external. In our area all the old barns and outbuildings are built looking like this, so it is in keeping, and one day I might even have a go at putting a thatch roof on it.

 

[masona]

Why not just have a concrete base and use 2nd hand pre-cast slabs(1/2 price), nuts/bolts them together then you can do what you like, timber cladding on the outside and insulation on the inner wall etc

I did this with my summerhouse, cheaper, strong & quicker

My summerhouse look like it's in Switzerland with the snow

 

[ESA]

Oops, I made some mistakes in my original note - the builder calcuated 960 blocks per skin, so approx 2000 blocks not 200

He also said it is £0.60 for concrete block, £1.00 for breeze block and £1 to lay them, so£2.60 per block excluding sand/cement, insulation, scaffolding, lintels and labour costs to hike them 30metres down the garden.

As for planning permission I am the most surprised of all but council have confirmed in writing that pp is not required, also looking at the conditions explicitly stated in p14 and p15 of the planning guidance booklet i would have to agree with the council guy that confirmed it http://www.communities.gov.uk/index.asp?id=1144635.

The maximum sixe for a detached structure/building on land around the house is 10cubic metres, not sure why certain councils state over 30m2 requires pp. Suggest you point them to the planning guidance booklet.

I will need building regs approval, and building regs have been round and inspected the ground saying I should dig 600mm*750mm deep footings.

There are 2 tree stumps on the land - trees have been dead for some time. Does this make a difference ? Building regs chap didn't mention it - was raining at the time so he may have been in a rush to get back.

Gangman, did you use insulation ? What do you use your outbuilding for ?

Masona - Can you please elaborate. Bit of a construction newbie.
Are you suggesting I concrete the ground first and then put concrete slabs on top of it or use the concrete slabs as walls ? Apologies for the amateur questions.

ESA

 

[gangman]

ESA
I didn't use insulation, but I built it so it wouldn't be a difficult job to put it in. One day I hope to convert it to habitable, might take some time but I've seen it done. I didn't want to make it to much like a dwelling just needed to get it built first.

I teach martial arts, so I used it as a dojo, matted floor, mirrors, bags etc. though no heating. Now though it's full of tools and materials as my garden was getting overwhelmed.

 

[masona]

Masona - Can you please elaborate. Bit of a construction newbie.
Are you suggesting I concrete the ground first and then put concrete slabs on top of it or use the concrete slabs as walls ? Apologies for the amateur questions.

ESA

I'm just thinking something simple like this for an example, you may not need the metal rod and the sizes can go a bit smaller for what you want,

Also see this to give you some idea, the back and 2 sides are pre-cast slabs with timber studwork on the front because of the 4 doors & 2 double windows, that is an old picture, I have another 2 summerhouse at the back forming an L-shape plan, got carried away there

 

[ESA]

Do you think 300mm would be sufficient given the building will be 8m x 8m and 3.5m high, with a pitched roof ?

Building regs chap said footings should be 600mm*750mm. He didn't mention using steel mesh or cages. May need to call him out again.

Any other views ?

 

[^woody^]

If you do a raft as pictured, then it will need to be designed professionally. You can't guess it or do an arbitary 300mm deep. It is a specialist foundation.

If you do a traditional strip as per the BCO recommendations, then you are OK. But unless the BCO dug a trial pit on his visit, then 750mm can easliy become much deeper when he sees the ground condition at that level