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Wednesday, 20 February 2013

Garden Office and Studio Foundations


Garden Office / Garden Studio foundations and base systems - your options explained


Oh no! This has got to be the most boring subject I have blogged about to date. B b but but here goes! (Sorry in advance if you find this a bit of a rant. Here it is and it did take a bit of thinking about!!!!) "Make sure next doors cat doesnt get concrete on his feet it burns"



Tigger from next door
 
THE GOLDEN RULES FOR FOUNDATIONS

  1. There is NO base type suitable for all sites.
  2. If you are using concrete (sometimes best) don’t order it before the shuttering is perfect. By perfect I mean strong, exactly the size of the building footprint, exactly the shape of the building footprint and accessible to the delivery – “you can use barrows or mix and pour but make sure the route to site works”. CONCRETE IS HEAVY! And you don’t get long to work with it.
  3. If you are using a timber frame base make sure NONE of the timber is in contact with soil and don’t forget that this needs to meet the footprint rule too.
  4. If you are using another system ask yourself – WHY? It’s no good asking your supplier because the answer from them in reality is “well that’s what suits us”
Here you can see a good example the building and the frame it stands on.
 

FROM EXPERIENCE AND RESEARCH The abc of Garden building foundations.

Having installed quite a few bases and made quite a few mistakes and read quite a lot of “bullsh**” about this subject before “putting fingers to keyboard” here are the important issues a b c and d only that is all there is.

a)      The purpose of the base is to transmit the load of the building to the ground. It must never move, sink, rot or break in any way during the whole life of the structure.

b)      It will (or should) NEVER be seen.

c)      It should cost no more than necessary to fulfil its purpose.

d)      It should not be disruptive in any way, which is unnecessary, e.g. create waste, damage surroundings or cause risk. It should not involve too much physical work (unless of course you want or “need” it).

e)      It should NOT cause an issue with planning or permitted development when considering the finished height of the structure. (Don’t jack up a 2.5m building over height using decking or a pad/jack base systems and expect to get away with it).
 
See how good this looks on a well designed base

THE COST £££ (you will never see)

The cost can be calculated this equation >>> Cost of base foundation =  (Access difficulty / the lie /slope/drainage/tree population of the land  * Chosen design + hired labour and tea bags etc.).

 

i.e. a sloping site accessed through the house using concrete with bad shuttering inexperienced labour and poor preparation will cost £A PACKET. A flat site with subsoil already removed accessible to the Shute of a concrete lorry will cost £NOT MUCH. A timber frame base correctly installed will cost £NOT MUCH either unless it jacks up the building over the planning permission limit.

CONCLUSION
 
Every Garden Office and Garden Studio site is different. This is a fact.

 

After 1000+ site visits and reading 300 + web comments, stories, case studies, DIY blogs etc. I have come to this conclusion.

 

Don’t re-invent the wheel – it is simple “No site is the same and no method fits all”

You need a base that does not rot, does not move, transmits the weight of the building to the ground, does not cost the earth and does not damage our planet.

 

I doing a bit of re-stating the obvious because I have seen it done wrong look at this!!!
 
What a mess I found on arrival - wrong size - not level - not square - not flat - not good!

 

  • Buildings need a functional foundation (The Shard is not standing on a screwpad DIY base)
  • The “next door neighbours son who needs a bit of work” might not know how to design and construct suitable foundations or clear up the mess!
  • Your chosen supplier for a new Garden Building will NOT be able to recommend the correct system if he or she has not seen the site.
A Quick summary

Design the base and select your chosen option taking into account the above.

 

To build a concrete base – Dig out the turf and topsoil, put in road stone, MOT, crusher run or whatever it is called in your area and level this. Vibrate to solid with a whacker plate. (If there is any doubt insert steel mesh when concrete is poured). Fix strong shuttering square and level measure everything twice and then lay a damp proof membrane. Pour the concrete and level to shuttering as you go. The wetter the concrete the easier it is to lay (excess water weakens the concrete but makes it easier to get a flat level surface).

 

To build a timber base use treated joists. Insert pads to carry the timbers at spacing which will not allow joists to bend. Fix the joists together. If the ground is sloping use concrete pillars or wooden pillars on concrete pads to ensure frame is level. Make sure there is no timber in contact with the ground and that air circulation is present.

END OF rant! …

 

Garden Office and Garden Studio Foundations. Written by Richard Grace Garden Structures Ltd Feb 2013   www.aarco.co.uk

1 comment:

  1. I guess it had to be done by someone!

    ReplyDelete