Fixing & Applications

Fixing Recommendations:

Setting up: Radially sawn Screen Boards can be fixed wide or narrow face out (NOTE: in most cases, they are fixed narrow face out). Depending on the thickness, Screen Boards can be fixed to rails or supports at centres of up to 1200mm but closer spacings will minimise movement or distortion (ie. 600 to 700mm max. centres would be advisable when fixing 19mm to 25mm thick timber).

Installation: The spacings allowed between seasoned DAR boards will depend on the desired look or function of the screen, however, a minimum spacing of 5mm should be allowed for swelling (NOTE: most privacy or sun screens are spaced at approx. 10mm). Unseasoned screen boards will shrink approximately 7% across their width so this should be considered when designing a screen.

Fixings: Boards can be hand nailed, gun nailed or screw fixed. Fixings should be at least 50mm long for 19mm to 25mm thick boards and at least 65mm long for 30mm to 50mm boards (NOTE: it is advisable to use stainless steel or hot dipped galvanised ring shank nails when fixing boards into treated pine, or twist shank nails for hardwood). Bevelled edge profiles may be “secret nailed” by skewing fasteners through the sloping sides but face fixing will give the best results. Pre-drilling may be required when fixing seasoned boards.

Seasoning & Storage: Some surface checking may occur if timber is exposed to the weather but these non structural cracks are typical in most Australian hardwoods. It is also normal for hardwoods to leach red/brown extractives during heavy rain periods. Extractives tend to be less prominent in lighter species but it is advisable to cover or protect walls and paving until all extractives have leached (can vary depending on rainfall but will generally continue for up to 6 months). Packs should be stored up off the ground and under cover or protected with an additional tarp to prevent swelling. If wetting does occur, allow a min. of 24 hours for timber to dry before fixing.

Suggested Applications

Radially sawn screen boards provide a unique alternative to imported rainforest and treated pine products and have been used in: feature walls, picket fences, balustrades, privacy screens, sun screens & pergolas. For images of Screen Boards visit the screenboards product galleries.

STORAGE & INSTALLATION OF TONGUE AND GROOVE SHIPLAP

Storage

Packs should be stored up off the ground on bearers and under cover or protected with an additional tarp to prevent swelling. When the cladding is delivered wrapped in plastic, it is important to check that the wrapping is not damaged and likely to allow water to be trapped within the stack. If wetting does occur, separate the timber with strips between each layer. Place in a well-ventilated area under cover and allow a minimum of 48 hours for timber to dry before fixing. Radial Timber will not be held responsible for incorrect storing of the timber.

Setting up

Shiplap cladding is typically installed in a regular pattern with the tongues and grooves of adjacent boards fitted together (see Figure1). Seasoned Shiplap boards will exhibit minimal shrinkage and will actually swell slightly in wetter regions or exposed areas (especially the west side of a building) making it essential to ensure boards have an approved gap to allow this movement. The secret fix shiplap has a slightly raised shadow line which will act as a guide. The neighbouring board should not be pushed beyond this point. Noggings, fixing battens or studs should be spaced at max. 600mm centres. If shiplap is run vertically a fixing batten may make installation easier.

Try to have the tongues of the shiplap facing into the direction of the prevailing winds as this will minimise moisture pressure being swept sideways during high winds into the rebated board

Installation & Layout

Preferably layout of the boards should be in a vertical position for better water runoff especially in very exposed locations such as near the coast. Boards can be fixed directly to breathable moisture vapour barrier clad walls however a better option is to use fixing battens on the studs. Use 75×35 treated pine batten fixed directly to the moisture vapour barrier clad stud walls, this also allows for good ventilation between the back of the boards and the moisture vapour barrier. It is also advisable to use a plastic horseshoe packing shim under the batten to alleviate and ventilate any build up between moisture vapour barrier and timber cladding (refer to technical drawings on our shiplap page on the website). Allowances must be made for the extra width cavity wall when it comes to windows, doorways etc. If fixed horizontally, the tongues of each Shiplap board should face up to prevent water from being trapped inside joints but the preferred recommendation is for this secret shiplap to be run vertically. On long runs, boards may have to be butt or splayed joined over battens with the use of a flexible glue/sealer on the joined ends. A better option is to use end matched boards, alternatively walls can be broken up into smaller panels by inserting a flashing or vertical/horizontal timber stops. Special Aluminium or timber stop profiles can also be used on external and internal corners and these are available from radial timber.

Board Spacing & Weatherproofing

Boards must be installed with a 5mm gap between them which is indicated by the shadow line which is a very slight raised section on the tongue (All boards have a 5mm gap). This spacing will allow for movement of the timber as ambient humidity and conditions change.

Boards exposed to the sun and rain (north – northwest elevation) will shrink and swell more than semi protected boards. Recommended expansion gaps are critical on these exposed elevations as is eliminating any butt joins (end matched options might be a better option to consider) and where possible provide some weather protection with eaves, veranda, or similar. Do not allow rain or water to get behind boards during installation. Wall cavity must be protected at all times. It’s important that all flashing around windows or other openings are adequately installed to allow for proper drainage away from the timber (refer to diagrams). If the shiplap is run vertically at the bottom of the boards make sure the boards are undercut to form a drip edge or a suitable angled flashing is installed. Care and attention should also be taken to avoid pooling of water when fixing other structures such as pergolas to the cladding as well.

Fixing Recommendations

38, 70 & 90mm shiplap boards can be fixed with small headed 50mm long 7 gauge (3.8mm) counter sunk stainless steel (304, A2 or 316 grade) screws and the wider 110 shiplap boards require a face fix only, standard 10 gauge (4.8mm) counter sunk decking screw as these don’t degrade like other metals. Care should be taken close to ends by predrilling to avoid splitting. (Radial can supply these self-countersinking stainless steel screws fixings). The screws should be installed on a slight angle so that they sit flush on the tongue allowing the over lapping board to lock into place against the shadow line. Holes can either be predrilled or self-drilling screws can be used into pine battens for the 38, 70 & 90 boards. If using the wider 110mm board, two 10 gauge screws are needed through the face of the board. Predrilling will need to occur for the wider 110 board and the hardwood battens.

STORAGE  & INSTALLATION OF SECRET FIXED Lining Boards

Storage

Packs should be stored up off the ground on bearers and under cover or protected with an additional tarp to prevent swelling. When the lining is delivered wrapped in plastic, it is important to check that the wrapping is not damaged and likely to allow water to be trapped within the stack. If wetting does occur, separate the timber with strips between each layer. Place in a well-ventilated area under cover and allow a minimum of 48 hours for timber to dry before fixing. Radial Timber will not be held responsible for incorrect storing of the timber.

Setting up

The lining boards are typically installed in a regular pattern with the tongues and grooves of adjacent boards fitted together (see Figure 1). The lining boards will exhibit minimal shrinkage and will actually swell slightly in wetter regions or exposed areas making it essential to ensure boards have an approved gap to allow this movement. The secret fix lining has a slightly raised shadow line which will act as a guide. The neighbouring board should not be pushed beyond this point. Noggings, fixing battens or studs should be spaced at max. 600mm centres. If the lining boards are run vertically a fixing batten may make installation easier.

Installation & Layout

Preferably layout of the boards should be in a vertical position for better water runoff especially in very exposed locations such as near the coast. Boards can be fixed directly to breathable moisture vapour barrier clad walls (if applicable).

If fixed horizontally, the tongues of each lining board should face up to prevent water from being trapped inside joints but the preferred recommendation is for this board is to run it vertically. On long runs, boards may have to be butt or splayed joined over battens with the use of a flexible glue/sealer on the joined ends.

Board Spacing & Weatherproofing

Boards must be installed with a 3mm gap between them which is indicated by the shadow line which is a very slight raised section on the tongue.  This spacing will allow for movement of the timber as ambient humidity and conditions change.

Boards exposed to the sun and rain (north – northwest elevation) will shrink and swell more than semi protected boards. Recommended expansion gaps are critical on these exposed elevations as is eliminating any butt joins and where possible provide some weather protection with eaves, veranda, or similar.

Fixing Recommendations

The lining boards should be fixed with small headed 50mm long 7 gauge (3.8mm) counter sunk stainless steel (304, A2 or 316 grade) decking screw or suitable nail.

If using screws care should be taken close to ends by predrilling to avoid splitting i.e (Radial can supply these self-countersinking stainless steel screws fixings). The fixings should be installed on a slight angle so that they
sit flush on the tongue allowing the over lapping board to lock into place against the shadow line. Holes can either be predrilled.

FIXING AND APPLICATION

Transport To Site

Natural edge weatherboards are supplied unseasoned and generally transported to site in log form with the ends uncut. It is not uncommon for logs to break open or boards to split during transport/delivery but Radial Timber Sales generally provides an additional 1 to 2m2 of boards in each log at no cost. If damage occurs, it is recommended that the split boards be put aside and only used as short in-fills around windows and doors.

Setting Up

The ends of each log need to be removed in order to release the boards. This is typically done by cutting in a min. of 350mm from each end of the log with a chainsaw. Once the log ends have been removed, boards spring free from the heart wood or core and have a slight but consistent curve, resulting from natural tensions in the log (see Figure 3). Studs should be spaced at max. 600mm centres.

Installation

Boards are generally installed in sequence by numbering the boards and following the profile of the log (NOTE: overall cover will be reduced if installing the boards in a random pattern). Before fixing the first board, the outer or sapwood edge may have to be cut square in order to remove any natural curvature. Remaining boards can then be fixed by eye (ignoring minor variations in cover) or by scribing the average cover onto weatherboard stops. A minimum board overlap of 30mm is recommended to allow for average shrinkage of up to 7%. First time fixing may take longer than that for conventional square edge boards.

Fixings

Boards can be hand or gun nailed but care should be taken close to ends to avoid splitting (boards may need to be pre-drilled if hand nailing). Typically, 50mm long hot dipped galvanised or stainless steel fixings should be used but it may be necessary to use 65mm nails if boards are thicker than 25mm (NOTE: it is advisable to use twisted shank nails when fixing boards into treated pine). Pre drilling the ends of boards prior to fixing may be required to avoid splitting. A fixing of two nail per board per stud is recommended.

Joining

When joining boards on long runs, the weatherboards should be matched for width and appearance by “book matching” or butt joining the ends of consecutive boards from a log. On long walls, it may be quicker to break up the wall into smaller panels by inserting weatherboard stops (ie. vertical timber sections). Weatherboard stops can also be used at joins on internal and external corners of the building (rough sawn 75x50mm sections and are available from Radial Timber Sales).

Cover

The average cover of weatherboards will vary within a single log or between logs; therefore, achieving the same cover for a whole wall may not be possible. If the effective cover appears to be less than 80mm, it is recommended that these boards be put aside and only used if narrow coverage is a desired effect.

Seasoning And Storage

Some movement may occur during seasoning but boards will generally settle as moisture content in the boards equalise (NOTE: unprotected west facing walls may be subject to extreme temperature changes and therefore, timber is more likely to move). Leaving boards in log form is the recommended way to store timber on site for extended periods of time (ie. logs can be stored for up to 12 months but it is be advisable to cover with a tarp or plastic).

Timber Leaching

It is also normal for hardwoods to leach red/brown extractives (tannins) during heavy rain periods. Extractives tend to be less prominent in lighter species but it is advisable to cover or protect walls and paving until all extractives have leached (can vary depending on rainfall but will generally continue for up to 6 months).The tannin staining can be cleaned with a diluted bleach/water mix.