Log Cabin Installation Guide
Log Cabin Installation Guide
cabins are made of a natural material and it is impossible to guarantee
an absolutely perfect finish to every part because of the natural
movement of timber. You must therefore expect to be prepared to carry
out some finishing/alterations yourself. By definition you must be a
competent woodworker and have the appropriate tools (saw, hammer,
chisel, drill, etc.). If you feel that you might not be capable of
carrying out this type of work then you should look to employ a
suitable contractor who is able to do this for you.
- Your cabin will be delivered in one large pack. The
first part of the installation process is to unpack the individual
items within the main pack and stack them near to the proposed site for
the building, at the same time counting the parts and checking them off
against the parts list which is supplied with the building. This stage is very important and you should not start to construct the cabin if there are any missing or damaged pieces. If the kit is incomplete you should report this immediately.
- The diagram below shows a typical excerpt from a base plan supplied with one of our cabins:
Click image to Enlarge
This plan shows a typical floor bearer layout for a cabin with an overall dimension of 3.0m. The interlocking notch is typically set in by 0.1m from each log end, hence the base measuring 2.8m.
Please note that the plan shows the spacing between each of the bearers as well as the width of the bearer on plan view. Floor beaerers are always laid flatways in order to allow for the floorboards to be fitted at the end of the job as described later on. Please note that they are called floor bearers and not floor joists, this is because they are designed to be supported by a sub-base. They are not designed to take the full load and span from one side of the building to the other.
- Once the floor bearers are positioned (please refer to note 9b), the first course of logs can be fitted. Log cabins use interlocking joints which rely on a staggered log height, consequently the first course of logs consists of alternating full height logs and half height logs as shown below:
Click image to Enlarge
- Build the
walls as shown on the plans provided, sliding the windows and doors
into position when there are around 5 courses of logs built up either
side of the window/door which help to hold them in place whilst you
carry on building building (please refer to our
website resources section at the bottom of the homepage if you have upgraded ISO
windows/doors). It is important that you do not fix any window or door frame directly to the logs, but wise to use packers to stop any unwanted sideways movement at the top of each of the frames (only use packers on the sides of the frames - they can be screwed or tacked into place, do not put packers on top of the frames as this will not allow the logs to settled down after the build is complete or during the change of seasons) - there is a deliberate gap either side to allow for final positioning of the frame. If you find that the door lock has the latch pointing in the wrong direction, you do not have to take the mechanism apart to change it but merely either pull the latch out, twist it round and click it back into place or push it in by releasing the gravity toggle, spin the latch around and click it back into place.
- If the cabin has a wall longer than 6m, then it should be built as follows:
The logs are joined in the middle of a partition wall or portal archway. The metal plate is supplied in long lengths which can be cut to length on site with snips or hacksaw. The joining logs should be tightly clamped and then fixed using a screw through the metal plate either side of the joint which will stop the logs spreading in the future. Every course of logs should be joined in this way.
NB- this method is not possible with 28mm logs as the banding is too wide to fit, therefore the 2 joining logs are each pilot holed and screwed into the common partition/archway log with appropriate fixings.
- If you are building a twinskin cabin, it is important not to fill the cavity up to the top of the walls because the walls will settle down and therefore the insulation would be exposed and could force the roof up. We suggest leaving a minimum of 60-70mm gap all around the top.
- Fit the gable trusses into position and secure by sliding the main roof purlin supports into the appropriate pre-cut notches in the gable triangles.
- (a) If you have an insulated roof/floor, the construction is as follows:
Screw the timber flanges to the underside of the purlins and screw the coving support to the side walls. We provide lengths of T&G boarding that will require cutting down to suit the gaps between the purlins (these should be cut around 10mm shorter to allow for movement and irregularities between the purlins).
Lay the short lengths of T&G boarding between the purlins, resting
on the flanges. Making sure that there are 10mm spaces at the start and
finish of each bay in case the boarding swells.
When each bay is complete, lay the polythene vapour barrier directly on top of the T&G boards, lapping it up all sides, then fix the holding batten into the purlin on
top of the T&G and vapour barrier. This allows for movement in the T&G whilst holding
it all in place as well as sealing the vapour barrier all around as well.
Fit the insulation between the purlins. (If you have the solid foam insulation kit, this will comprise of 1 layer of solid foam insulation placed directly onto the short lengths of T&G and then 1 layer of 100mm fibreglass insulation over the top which will fill the whole of the cavity making a "warm deck" roof). Make sure that it is a tight fit all round.
Once this step has been completed proceed to the next step. It is
possible to complete this step after the main roof has been fitted but
it is much easier to work from bottom to top with a 2 layer roof.
(b) The photo below shows how to close off the under floor insulation from being exposed to the elements.
The timber fillet can be simply fixed to the ends of the bearers, or if you wish, the bearers can be trimmed a little to allow for the thickness of the fillet (each fillet being 8mm thick) and therefore giving a flush finish.
- Nail the tongue and groove roof boards in place by starting at one end and
working along, checking the distance covered at the top and bottom of
the boards to ensure they are running parallel to the walls (this will
avoid cutting a wedge-shaped final board).
NB Do not fix the roof boards tightly together as they may swell and cause damage to your roof structure and felt.
the side baulk to the underside of the protruding Tongue and grooved
roof boards along the eaves, this will then form a drip for your felt
to dress over:
Once the felt has been fitted, the barge boards and fascias can be fitted which helps to hold the felt down.
the building has been weathered in, it is safe to lay the floor
without danger of it being exposed to the elements. Use the same
principle as used with the roof, ie. start at one end and work towards
the opposite wall, always checking that the remaining gap is equal at
either end of the boards to avoid having to cut a wedge shaped final
board to finish.
NB Always allow at least an 8mm gap between any wall and the floor boards to allow for expansion.
- Fit skirting boards and any finishing trims that are provided.
- Finally fix the clamp baulk as shown below:
Once the cabin has been installed it is very important that it is painted with a high quality preservative/stain immediately (all of the exterior as well as the interior including the ceiling), the exterior coating must also be water repellent.
It is very important that anything fixed in the vertical
direction is done so using flexible joints (ie slots) to allow for future log
movement (ie- shelving, electrical conduit, cabinets, etc.), and allowing at
least 50mm of expansion or contraction gap.
Adjustments: Once built, log cabins will take approximately 2/3 weeks to
"settle down", where the height of the building will reduce by at
least 25mm. Inevitably this could cause some of the doors/windows to bind
slightly, this is easily rectified by using the adjustable hinges to re-align
the door/casement. We are not responsible for these adjustments.
Sometimes the frames may need re-squaring as well, again this is easily done by
unscrewing the 2 internal side architraves, re-squaring the frame (equalling
out all of the clearance gaps around the casement/door), temporarily wedge in
place, then measure the gaps between the frame and the logs at either side of
the frame, cut some packers just slightly less than the gaps (you do not want
to wedge it so tightly that the logs are unable to move up and down) and screw
or tack the packers into place. Finally remove the temporary wedges and replace
the side architraves.
Further helpful hints and advice can be found at http://www.hortonsgroup.com/faqs_all/5