Technical specification – Keops Interlock code of practice

This code details the best practice for standard and optional features of a log cabin design. This information can also be found on “The Blueprint”. You can request a copy to be sent by post, or download as a PDF.

Design overview

Specify which optional features are to be included in the cabin design.

Cabin footprint

Specify any width x any depth; dimension to the outside faces of the wall.

Roof style

Specify Classic ridge, Dutch, Quatra, Moderna or other.

Roof overhangs

Partition walls

Specify any layout of partition walls; use same log thickness.

Floor joists

Pressure treated; for non insulated / comfort grade insulated floors use 58mm x 58mm; for building regulations insulated use 50mm x 100mm, for mobile homes use 50mm x 150mm.

Floor boards

Use 19mm thick tongue and groove pine; optional 22mm P5 chipboard.

Wall logs

Only use PEFC Northern Scandinavian pine 5 star selected grade to ensure straightness, stability, high density, free from excessive splits, loose knots or sap; kiln dried; use 28, 33, 45 or 56mm thickness, depending upon application, x 130mm tall; robust tongue and groove providing deep engagement (double on 56mm log); precisely machined corner joints to provide vertical and horizontal interlocking; no finger joints in the length; all logs from same source and batch; rounded log ends (square ends for Moderna and Cottage style) x 95mm protrusion; manufacture in factory with minimum 35 years experience. Butt joints of long longs to be staggered either side of of a linking wall; apply silicon seal during construction and after decorating.


Specify any position; laminated frames to limit warping and openings fitted with gasket seals, fit latch, five pin euro cylinder mortice lock and stainless finish handles.


Specify any positions; gasket seals to all openings; fit handles.


All frames to ‘float’ in walls to avoid obstructing natural swelling and contraction of wall height.


Refer to tables for optional grades of glazing

Roof beams

165mm x 58mm structural white wood, milled all over; max unsupported span 4800mm; support with solid roof truss; optional open frame truss.

Roof boards

Use 19mm thick tongue and groove pine; with decorative ‘V’ groove.

Roof coverings

Use superglass bitumous felt shingles in colour green, brown or black for up to 15 year life; fixed with galvanised clouts or heavy duty staples; alternatively heavy weight shingles; alternatively metal profiled sheet with pressed tile pattern; alternatively cedar shingles, alternatively Tapco imitation slates.

Roof strength

Rated to carry 70 kgs/sqm.


Specify any size; commonly 1000mm deep.


Specify any size; interlocking log balustrade; pressure treated decking boards 95mm x 22mm; commonly 1500mm deep.


Use PVC; 50mm pipe, 100mm trough.

Floor insulation

Rigid urethane products foil faced both sides; For comfort grade use 50mm (U=0.4); for building regulations use 80mm (U=0.25).

Roof insulation

Rigid urethane products foil faced; for comfort grade use 50mm plus OSB 11mm (U=0.38); for building regulations use 154mm (U=0.16); fit vapour control barrier and breathable membrane.

Wall insulation

Provide double walls with 90mm cavity between for insulation; 45+90+28=174mm wall thickness; use rigid urethane products foil faced both sides 70mm (U=0.3); fit vapour control barrier and breathable membrane.

Wall battens

Any vertical member attached to walls shall be held with a sliding bracket system to avoid obstructing natural swelling and contraction of wall height.


Supply in component form; palletise, band and wrap; max pack size 6000mm long x 1200mm tall x 1500 kgs.


On articulated vehicle with 13.6m trailer; forklift truck on-board.


Specify forklift truck offload; to avoid manual handling health and safety dangers; to keep packs intact, well supported, weather protected, off road.


Prepare a suitable platform that is flat, level and stable; usually concrete 100mm thick and 100mm larger on all sides; alternatively paving on well compacted hardcore bed approximately 150mm deep; alternatively timber open framework structure typically 200mm x 75mm and 150mm x 50mm pressure treated members positioned as advised by the cabin supplier.


Either self build by two able people minimum with skill and knowledge of construction techniques and suitable tools, access equipment and safety equipment; or specify construction service anywhere by Keops experienced teams with fully equipped vehicles and specialist tools and know how.


Conceal wires within roof insulation for lights and switches; form wooden skirting with void behind to conceal wires for sockets, telephone or computers etc.


Externally apply 1 coat clear wood preservative and 2 or 3 coats of Sadolin Classic, Supercoat or Superdec or other similar ‘5 year’ waterproof protection; waterproof protector to have colour pigments to provide UV protection; reapply at 5 year intervals or as necessary: internally apply 1 coat clear wood preservative; in damp interior environments seek advice; apply silicon sealant to log butt joints after treatments and to corner joints or window surrounds if necessary; Fire proof to class O spread of flame with HR-PROF product if necessary to meet building regulations.

Planning permission

Review current policy for permitted development of out buildings at or check with local authority.

Building regulations

Applies to structures over 30 square metres internal floor area and dwellings; mobile homes will be exempt from building regulations.

Caravans & mobile homes

Shall have maximum size 6.8m wide x 20m long x 3m internal height, minimum length 7m; must be moveable in one or two pieces.