SBS design guide - proof 20 - Sip Building Systems

1 design guidePart 1:Structural DesignSBS design guide - proof 20 5/2/09 10:21 Page 2 design guidePart 1:Structural DesignTel: 0870 224 :Fast EconomicalStrongInsulatingEnvironmentall y friendlyVersatileOffsite fabrication means that your weatherproof Building shell can be complete just a fewdays after the groundworks are ready to receive them. Internal and external work canimmediately follow on together. SIPs use less timber than timber frame and are one of the most economical and eco friendlyforms of construction. The high strength and low weight of SIPs allow large sections of Building to be lifted in onepiece for speed of erection but the panels may also be erected one at a time by hand whereaccess is roofs do not require support trusses, leaving clear, warm, habitable roof insulation exceeds the current Building Regulation requirements on its are fabricated using timber from sustainable sources.

2 Offsite fabrication reduces , and light unit weight, also reduce embodied and transport energy. Their high insulationand airtightness reduce the major sources of Building energy use, making them one of the greenest construction materials. The foam insulation is (Ozone Depletion Potential ODP)zero and has a low GWP (Global Warming Potential).SIPs, through their strength and ease of connection, offer the designer more versatility thanother construction materials, allowing possibilities beyond the conventional, such as slopingwalls and all with the advantages of offsite Modernist house supplied by SIPB uildErecting panels by crane aboveand by hand belowVernacular house supplied by SIPit (Scotland) LtdSBS design guide - proof 20 5/2/09 10:21 Page 3 Structural Insulated Panels (SIPs)SIPs are a sandwich of Oriented Strand Board (OSB) with an insulating polyurethane foam OSB and the foam are rigidly bonded together resulting in a strong, stiff, highly insulatedpanel suitable for structural use in buildings.

3 SizesOur standard range of panels has three thicknesses, 100mm, 125mm and 150mm, and panels areup to wide and long. The face boards are normally 11mm thick OSB3 (for structuraluse in damp conditions). Other thicknesses and constructions are available on request, including15mm face boards, particle board faces and up to 200mm thickness are made using expanding polyurethane glue and nails or screws. This ensures strongairtight are joined edge to edge by gluing and nailing fillets into their rebated edges. These may beeither thinner SIP fillets or timber. Timber fillets are used when additional strength is needed. Rebated wall panel bases slot over pre-fixed timber sole plates and are secured with glue and roof panels rest on triangular timber eaves fillets and are secured with glue and openings, such as window reveals, are lined with inset timber to allow easy fixing of may be sandwiched between upper and lower walls or may be attached to panel inner faceswith joist hangers.

4 Floors are usually made from engineered joists but SIPs may be used in somecases, particularly where the underside is open, such as over passageways. Floors may also besupplied in cassette interior after erection and house supplied by Edward Halford LtdSBS design guide - proof 20 5/2/09 10:21 Page 4 design guidePart 1:Structural DesignTel: 0870 224 are usually used in roofs and external walls of buildings but may also be used in floorsand internal walls. Their high axial load capacity and good bending strength, together withtheir excellent insulation and air tightness, produces sturdy warm structures. The current BBAcertificate covers two storeys plus roof storey. However, the system is not necessarily limitedin this respect and four storeys or more are possible when independently DesignLike timber, SIPs are stronger and stiffer along the grain and they undergo creep and sheardeflections.

5 In axial compression it is safe to use the values given for the panel propertiesbelow. Shear deflections are greater than in timber because the foam core has a lower shearmodulus and in most cases the shear deflections dominate. Creep is also more importantthan with most other structural materials. The method of calculating safe spans is given below after the safe span tables. Deflection isalways the governing criterion. It should be noted that continuous beams where sheardeflection is significant do not behave as ordinary continuous has been demonstrated that floors and roofs are capable of spanning two ways, bothlengthwise and transverse to the joints. This reduces deflections below the one-way spanvalues that are given below. Deflections may also be reduced with help from non-structuralitems such as roof counter battens but no testing to check such effects has yet beenundertaken.

6 SBS SIPs BBA accreditation:SBS SIPs are the subject of British Board of Agrement Certificate No. 06/4312 which is available on request or may be downloaded may be used in other situations not covered by the BBA certificate, provided that priorapproval is obtained from any relevant checking authority. In the case of buildings fallingoutside the range covered by the BBA certificate the local authority Building control mightneed to be satisfied. Depending upon the circumstances, reference to this design guide mightbe sufficient or it might be necessary to employ the services of a structural or civil SBS technical department is able to advise in all circumstances. 3 Modernist town house supplied by SIPit (Scotland) LtdTraditional house supplied by SIPit (Scotland) LtdTall Building clad in SIPssupplied by SIPB uildSBS design guide - proof 20 5/2/09 10.

7 21 Page 5 IndexPageDescriptionRoofs6 Table 1 Short term spans for different panels6 Table 2 150mm unreinforced horizontal single span roofs7 Table 3150mm unreinforced 30 slope single span roofs7 Table 4150mm unreinforced 45 slope single span roofs8 Table 5150mm unreinforced 60 slope single span roofs8 Table 6150mm reinforced horizontal single span roofs9 Table 7150mm reinforced 30 slope single span roofs9 Table 8150mm reinforced 45 slope single span roofs10 Table 9150mm reinforced 60 slope single span roofs10 Table 10150mm unreinforced horizontal two-span roofs11 Table 11 150mm unreinforced 30 slope two-span roofs11 Table 12150mm unreinforced 45 slope two-span roofs12 Table 13150mm unreinforced 60 slope two-span roofs12 Table 14150mm reinforced horizontal two-span roofs13 Table 15150mm reinforced 30 slope two-span roofs13 Table 16150mm reinforced 45 slope two-span roofs14 Table 17150mm reinforced 60 slope two-span roofsFloors15 Table 18100mm unreinforced single span floors15 Table 19150mm unreinforced single span floors15 Table 20200mm unreinforced single span floors16 Table 21100mm reinforced single span floors16 Table 22150mm reinforced single span floors16 Table 23 200mm reinforced single span floors17 Table 24100mm unreinforced two-span floors17 Table 25 150mm unreinforced two-span floors17 Table 26 200mm unreinforced two-span floors18 Table 27 100mm reinforced two-span floors18 Table 28 150mm reinforced two-span floors18 Table 29 200mm reinforced two-span

8 Floors19 Properties of unreinforced Panels20 design method for unreinforced simply supported sloping roof panels21 Deflections of unreinforced simply supported sloping roof panels22 Properties of reinforced Panels23 Deflections of reinforced simply supported sloping roof panels24 Racking resistance calculation for panels according to BS 5268 method25 SIPs as box beam lintels25 SIP box beam calculation26 SIP box beam rolling shear26 Moisture mount26 Axial load capacity4 Modern house supplied by SIPB uildModern bungalow designed for disabledoccupant supplied by Edward Halford LtdSBS design guide - proof 20 5/2/09 10:21 Page 6 design guidePart 1:Structural DesignTel: 0870 224 for using the following tables1. The tables are based on limiting deflections in accordance with Eurocode 12.

9 The dead load must include the panel self The dead and live loads in the tables are permissible (not ultimate) Eurocode 1 separates the effects of dead and live loads for The values given are for use in dry conditions (as BS 5268 class 1 & 2)6. The deflections are mean values as would be expected in a roof of several panel The panels are more consistent than timber. Tests on a batch of 32 panels showed that thestandard deviation of deflection was about 5%.8. Panels may be reinforced along their edges with timber. Values for 150mm panels reinforcedwith 38mm x 128mm wide grade C16 timber along each edge are given below. Thereinforcement must be glued with expanding polyurethane glue and screwed at 150mmcentres to the face boards. At joints this will be a single timber 76mm The tables for floor spans and roof spans differ because the Eurocode 1 factors ( ) aredifferent for floor loading and snow Increasing the face board thickness will not always produce an improvement in bendingstiffness because it will also reduce the shear stiffness of the The tables for two span beams are for the condition with both spans equally for multi-span SIPs are difficult.

10 The tables may be used to estimate most realcircumstances. If more accurate calculation is needed please contact our SBS is continuously developing the product and its manufacturing Systems and has anongoing testing program. This guide relates to products being manufactured in 2008 using thetest data available at that date. Creep is affected by many factors. The figures in this guide arebased on a small number of tests and are for guidance in typical situations. Where creepdeflections may be critical a conservative approach should be The initial table for SHORT-TERM loading is given for comparison between the different paneltypes and other manufacturers panels. These values may be used for walls subject to windloading but should not be used for medium or long-term design .