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Raised timber base installation guide

Method of construction of the Hortons raised timber base

1)  47x150mm tanalised timbers are fixed together to form the ring beam around the outer edge (the timbers may need to be cut down to suit your cabin as they are supplied in standard lengths, please check this before assembly), which is then chocked up to be level and square (just above ground level, giving under floor ventilation) to form an outer ring beam for the main cabin walls to bear on. 

2)  This then dictates where the corner posts are to be concreted into the ground. Once the corner holes are dug, the plastic posts can then be offered into the holes, cut off to the correct length (the posts are supplied in long lengths to give flexibility for the lengths required, we allow a nominal 400mm length per post), bolted to each of the timbers it is in contact with (lengths of threaded rod, nuts and washers are supplied with our kits) and concreted in using the quick setting postmix which is also supplied with our kits. 
3)  Further intermediate plastic posts are then fixed onto the outer ring beam in the same manner as the corner posts at no more than 2m spacings.
4)  The position of the internal joists can then be marked around the outer ring beam timbers. Joist hangers (supplied with the kit) are then fixed according to the marking out and the internal joists fixed into the joist hangers. 
5)  If the span of the internal joists is greater than 3m then intermediate plastic posts are required which are are bolted to the joists in the same manner as the outer ring beam.
 
Because the postmix is quick setting the base is now complete and ready for the cabin to be installed upon it immediately (it is wise to leave the temporary chocks under the base for about 48 hours whilst the concrete attains it's maximum strength..

It is also possible that more materials may be required once the groundworks have started (there may be soft ground or tree roots where posts have to be moved in order to span across them or if heavy equipment is to be installed where an extra post may be required for extra support, etc.), this is impossible to allow for before this point but can be supplied very quickly to avoid delays. It is the customers responsibility to ensure that reasonable precautions have been taken if potential problems are known beforehand (ie if heavy loads are to be put onto the base especially if they are concentrated in one area, built up ground, hard ground in the summer which becomes soft ground in the winter due to rising water tables, etc), in order to alleviate any future problems (ie subsidence). It is not possible to guarantee the stability of the base unless a ground survey has been carried out and structural calculations have been made by a qualified structural engineer.
 
If the site has a slope and the base needs to be elevated more than 400mm above ground level, then we suggest extra diagonal braces be used on the corners to avoid "racking". If in doubt, consult a structural engineer.

This forms a very sturdy base onto which the cabins can be built directly, giving major time advantages over the more traditional concrete bases.

If the building is greater than 30 sq m internal floor area, then building regulations will apply. We are able to upgrade the raised timber base to comply with building regulations at extra cost - this cost can not be determined until calculations have been made by a structural engineer (at extra cost) and also inspections have been made by a local council building control officer once the work has commenced, who will determine the depth of holes required for the posts which is subject to site/soil conditions.

 

Call us on 01403 888 222
Open 7 Days

All prices displayed are inclusive of VAT at 20% (unless otherwise stated)

Site Updated 08-September-2014


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