The Technical Information you need to know about our Post and Beam system
About the Timbers
All Natural timbers are supplied with a sawn finish but Posts, Beams and Rafters can be be supplied with a planed all round finish. If you order timber fascia and barge boards, these will generally be smooth planed to exposed side and edge.
All Post, Beam, Bracing & Cladding timbers are supplied ‘in the white’, i.e. untreated and undecorated, ready for you to use whatever finish you wish. If you are having an oak model it may be left untreated but for Douglas Fir models we recommend you treat it for resistance to water & UV. An example product would be Treatex Douglas Fir Protection
All other softwood framing and roofing timbers are pressure treated with Protim E406 UC2
As with all buildings it is essential to have a sound, level foundation that is set on solid ground.
For timber frame garages, carports, stores, workshops and similar buildings, most people choose to lay a concrete slab, usually at least 150mm (6”) thick and with some steel reinforcing mesh in this. If the building and/or the floor is to carry very heavy loads you may need to have the foundation specially engineered to comply with the requirements of your local Building Control department.
When using a Slab, we recommend that the size be 25mm greater all round than the footprint of the building. This ensures the Base Plate bolts can be installed without breaking the corners. Also the last sheet of cladding can be kicked out over the slab to guard against water ingress.
Sometimes it is desirable to have the floor sloping slightly, for example toward garage entrance doors so that any water that drips off vehicles can drain away.
Where a concrete slab is NOT required, e.g. if a gravel drive continues under a carport, then post base pads may be acceptable, providing these are set on a solid base. Sometimes a reinforced concrete slab may suffice, and we also offer special “Swift Plinth” concrete post bases which can be incorporated in your SolidLox kit.
The required foundation type is usualy decided upon by relevant information such as soil conditions, frost heave, proximity to surrounding vegetation, landscape contour (slope of site), fresh landfill, clay, sandstone, loamy soil, water table and structural load. You should refer to your local builder for full advice on a suitable foundation type.
The Adjustable Post Bases
If the concrete slab or other floor slopes slightly, or if the foundations are out of level, this could cause a problem with the structure. Since all posts are the same length, if the base of any of these were not level, then there could be difficulty in levelling these up so that the beams running between them – and that have to take the roof or other structure above them – are also level.
It is also desirable to ensure that the bottoms of all posts are kept out of any water that may lie around. (It’s OK for wood to get wet, but it must be dried out and kept well ventilated so that it does not remain damp).
Fortunately our building engineers have thought of solutions for both of these problems for you. They have designed in adjustable post bases as part of your Solidlox kit. Each of these is fitted with coach bolts onto the bottom of each post.
If there is any difference in the level of the foundations for these, the height of the base can be screwed up or down (max 50mm) so that you can get them all exactly level. At the same time, the sturdy galvanised metal base keeps the bottom of each post raised up out of any water, able to be kept dry, well aired, and damp free.
The very bottom of these post bases is then bolted down to the concrete or other foundation, to be held in position and free from any uplift forces that may occur.
Room Above Insulation
When opting for insulation in our room in roof Garages, Carports and similar, our standard specification is intended for incidental and storage use, with no permanently installed heating system. This should be made clear on any Building Regulations application for the structure otherwise you may be asked for possibly slightly “over-the-top” standards for such ancillary buildings like a ventilated space and breather membrane behind external cladding and a Vapour Control Layer on the inside face. The Local Authority will often also require a much higher fee for assessing the application! (approx £500 – £600 as opposed to approx £200 for an unheated, non-habitable space)
This is the same construction detail as would be applied to e.g. a house extension, and in most cases is unnecessary for ancillary buildings, since they tend not to be permanently and continuously inhabited where there is limited condensation risk.
Habitable Room in Roof specification
When requesting our Habitable room in roof specification it will include:
For the gable walls (and any raised eaves walls if required):
- Increasing the size of the stud framework to 140 x 38
- External battens
- 9mm OSB sheathing
- Breather Membrane
- 120mm insulation
- Polythene VCL
- 49mm Composite plasterboard
For the roof and floor:
- 160mm insulation between rafters and floor joists
- Polythene VCL
- Plasterboard under joists
Assembling The Kit Yourself
Although we recommend that a local builder installs your Post & Beam structure for you, the SolidLox system does enable you to install it yourself with the assistance of a qualified Carpenter or Builder with Timber Frame knowledge.
If you choose to self install, the following should be considered:
- To erect the Post and Beam base frame it should be possible to do this using only hop ups. Above this you will need an access platform and scaffold towers can provide a quick and convenient solution
- For installing the sarking, breather membrane and counter-batten on the roof we recommend that two roof crawler ladders are used (These are the ones that ‘hook over’ the ridge to prevent them slipping down). This is also advisable for fixing the actual tiling batten and tiles / slates.
General fixings are not included. You will need sufficient quantity of the following items:
- 100mm Oval Nails (or gun nails) for nailing wall frames
- 100mm Oval Nails (or gun nails) for nailing roof timbers
- 50mm sherardized round head Nails for feather edge wall cladding
- 50mm sherardized round head Nails for fixing OSB sarking to rafters
- 75mm sherardized round head Nails for fixing counter batten through OSB to rafters
- 60mm Screws for floor deck (10 per sheet) – If having a room in roof option
- Glue for floor deck (1 tube per 8 sheets)) – If having a room in roof option
For longer life, Nails & Screws should be non-corrosive or stainless steel
Decorating and maintaining your Building
When using OAK Many people choose not to apply any treatment or finish whatsoever and allow the timber to ‘grey out’ naturally. Others may prefer to add some form of oil, wax, varnish, or paint to match in with other decoration or construction materials.
Douglas Fir should be treated and maintained for resistance to water and UV. An example product would be Treatex Douglas Fir Protection
Larch and cedar timber cladding can be left to ‘grey out’ naturally, although if less durable timbers are used then some form of paint, or bitumen treatment may be desirable.
Normal decoration and maintenance of timber then applies.
Properly treated and maintained, these structural timber buildings can last for hundreds of years. There are many examples of timber framed and timber clad buildings all over the UK that have outlasted masonry and lesser structures.