STANDARD TIMBER FRAME SPECIFICATION AND GENERAL TERMS

1. Structural Integrity
The timber frame will be designed to meet the requirements of BS 5268 Part 2. In order to meet Building Regulations requirements, Big Timber will provide a detailed file prepared by our Structural Engineer proving the structural integrity of all the timber frame elements and the stability of the structure.

2. Setting Out the foundations
Big Timber will set out the sub-structure works by theodolite as a part of the timber frame package. (We do this to eliminate dimensional discrepancies).

TIMBER FRAME SPECIFICATION:

3. Ground Floor Plates
140 x 38mm double tantalised or equivalent treated sole plate on 150mm dpc anchored to level oversite. 600mm wide horizontal lapping course radon barrier (if required) positioned at dpc level and protected from construction damage by being temporarily tacked up onto the inner wall faces.

4. Under-floor Heating
If Clients intend to incorporate under-floor heating, Big Timber need to take this into account when calculating the wall panel heights. Client to advise Big Timber prior to manufacture.

5. First Floor
Depth of joists to match spans but generally 220 x 47mm. Longitudinal blocking at 2.5 m centres, 22mm twice seal-coated t+g moisture resistant chipboard flooring, glued with waterproof PVA in the tongues and with P U glue between the floor sheets and the joists. This is done to reduce the possibility of the floor creaking. Alternatively, if it is anticipated that the roof covering work will be delayed, the floor shall be constructed with 18mm plastic coated t+g moisture resistant chipboard flooring. (No cost implications.)

6. Beams
Beams spanning wide open plan areas will, where possible, be designed to fit in the floor void, using primed steel as necessary. If an exposed 'drop' beam is required we generally construct these in laminated Swedish Redwood.

7. Wall Panels
140 x 40mm vac vac treated CLS frames comprising studs at 600mm centres, top rail and bottom rail, integral lintels to match span of window/door openings, but generally 220 x 140mm. 40mm x 140mm sole and head plates. 9mm osb3 sheathing, breather membrane lapped 200mm fixed with stainless steel staples. 50mm x 50mm treated timber cavity closers, dpc around window openings, perimeter walls ready to receive the following:- 150mm dense rock wool or similar, shrouded in well lapped 500g vapour barrier and finished with mechanically screwed 12.5 mm t apered-edge plaster board.
Please note: Insulation, vapour barrier and plasterboard by others unless specifically indicated in the contract quotation).

8. Binder Plates
Head binders of similar size to the wall panel thickness are installed to provide stability.

9. Load bearing partitions
38 x 89mm at 600 centres with mid rail support. Stiffening sheathing as required.

10. Non load bearing partitions
40 x 89mm frame at 600 centres left ready for first fixers.

11. Noggins
Ceiling noggins are not provided, this is because it is more practical to use 15mm 'self strength' plasterboard and, plasterboard tackers use differing sizes of board. If noggins are required our carpenters will provide these to instructions for a reasonable price.

12. BIG TIMBER PRINCIPAL ROOF TRUSSES
Generally formed out of SC3 or SC4 kiln dried Redwood. Bottom chord nett size 135mm x 290mm. Rafter Chords and Tie Chords 135mm x 190mm. Purlins vary with span but generally 210 x 190mm. All joints glued and pegged.

12 a. Stressed skin roof panels accompany Principal Trusses and, subject to SAP calculations, the insulation component is generally 160mm of Cellotex insulation, over 500g visqueen vapour barrier in a stressed skin panel format consisting of 190mm x 38mm treated rafters at 600 centres. These are strengthened by 9mm osb3 sheathing, nailed in accordance with BS 5268 requirements.

13. Pre fabricated gang nail roof trusses
Erected at 400 or 600mm centres, braced to manufacturers’ requirements, and optionally priced breathable roof felt and battening, white, pre formed upvc fascias and soffites. Soffites shall be vented if breathable felt is not specified.

14. Attic Trusses
Erected at 400 or 600 centres and braced with precut OSB3 laid between the trusses, these bear onto ex 50x 50mm treated noggins.

PAYMENT TERMS:

For drawing work:- Payment when drawings have been produced. We normally charge for these through an associated consultancy : ‘Village Home Designs’. The fee invoices are not subject to VAT.

For straight forward house frame contracts the terms of payment are :-

The first payment; a deposit of fifteen percent of the lump sum specified in the quotation, at the time of ordering the actual frame.

The second payment; a sum equal to 65% of the contact sum, shall become due on the day of delivery to site of the timber frame and Big Timber will notify The Client three days beforehand that the building has been manufactured at the works and is ready for dispatch.

A final payment of 20% of the lump sum specified in the quotation, adjusted to take account of any omissions or additional sums for authorised and approved variations shall be paid upon practical completion.

On larger contracts and when Big Timber is providing windows, insulation, joinery etc., additional stages shall be mutually agreed with the Client.