SIP panels are factory-laminated sandwich panels with insulation borded between two boards. The panels are used for roof, bearing wall and non bearing wall, as the structural frame and facing buildings for resisting transverse, axial and racking shear loads of oriented strand board (OSB). Kingspan TEK® utilises Kingspan’s high performance, fibre-free rigid thermoset Urethane Insulation for the core of the SIP Panels.
Panels are connected by nails or staples and a polyurethane based sealant. Screws of equal strength may be substituted for nails and staples when used at an equivalent frequency. However, a polyurethane based sealant must be used together with all fastening techniques.
Sill Plates and Splines
The sill plate is a lumber, which attaches to the building structure and fit into the recess at the base of the panels. Splines are used for connecting panels together and they can be lumber on SIP. Both sill plates and splines must underlay SIP panels along entire length of a panel run. When a wall is mounted to concrete a treated secondary sill plate and a sill seal material is used. In addition, always maintain a minimum 20cm distance between soil and panels.
When installing roof panels, the use of lifting equipment is highly recommended. After roof panels are installed, all panels must be fastened to the beams, trusses and bearing walls of structure. Construction adhesive is required any time the roof panels meet a wall or beam. Usually, roof panels are fastened 30cm on centre with SIP screws and washers. When the roof panels are completely installed, fastened and gaps filled with expanding foam, roofing should be applied as soon as possible. Panels used for roof systems must have a minimum temporary roofing applied at the time of installation.
The use of vapour retarders is recommended when mandated by code or climatic conditions and also at SIP roof ridge connections and on all SIP applications that are interconnected with dimensional lumber splines.
Internal and External Finish
12.5mm standard plasterboard must be installed on the interior face of the wall and roof panels and on the underside of floor panels having occupied space beneath. For exterior finish any material from bricks, natural stone, brick stone, brick tiles, polymer and cement renders, timber cladding and metal cladding can be used. Roof finishes can include various lightweight systems as well as traditional slate or tiles.
Inner Wall Installation
Where the lumber is dry water is sprayed onto the surface to provide a better grip for the polyurethane to stick on the lumber spline. Polyurethane is sprayed into the recess side of the panel and on top of the base plate. The bottom corner of the panel acts as a pivot and the other side is leaned against the neighbouring SIP. The panel is then simply pushed into place, allowing gravity to do the rest. If necessary, the panel can be nudged with a persuader block to make it level. When everything is level the SIP is nailed or screwed into the lumber spline along the side and bottom edges on both the interior and exterior surfaces for added strength.
Corner Wall Installation
Polyurethane is sprayed onto the lumber spline. The spline is nailed or screwed to the panel every 20cm on the centre. Polyurethane is sprayed into the recess side of the next panel. The panel is placed over the base plate and pivoted up on its corner into position. For side panels the meet at the corners of the building, the lumber board is nailed or screwed on the side of the SIP. The corner SIP is positioned and nailed into place in the same way as the other panels.
Exterior Wall Installation
Exterior wall construction with SIP’s is exactly the same as interior wall construction. Here the corner SIP is raised by sliding its corner slowly along the base panel and rocking it into position against the 2×6 board which has already been secured along the edge of the other panel. From start to finish building with SIP’s is easy and saves considerable time compared to conventional construction methods.
Thermal Resistance and Fire Performance
SIP’s have very little surface area for conductive heat loss because of their unbroken layer of high density insulation. Therefore the tightness of the system minimises gaps and prevents air leakage through out the construction. SIP systems provides wall and roof assemblies with higher effective thermal resistance than other construction methods. As a result with this system there is a reduction up to 40 to 60% in heat loss. These insulating values can reduce heating and cooling costs and improve the overall efficiency of building. Depending on detail of construction U-values for a call can be in range of 0.20 to 0.10W/m2k or better. Structural Insulated Panels exceed the Building Regulation requirements with regards to fire resistance, with 12.5mm fire resistant plasterboard the panels achieve a Class 1 fire rating. A Class 0 fire rating is achieved when two layers of plasterboard are fixed.
As always use caution when lifting panels, keep all personnel clear of the overhead load. Panels may be lifted by hand or with mechanised equipment. When a crane is to be used to lift a panel into position, care must be taken in rigging the panel to avoid damaging the edges of the OSB with slings.