Frequently Asked Questions
Many different constructions can be used but the tolerance to level must be +/- 5mm to ensure the most efficient erection of the SIPs panels. The most common practice is to build up a dwarf wall in block from the poured foundations which the SIPs are fixed to.
Foundations for SIPs tend to be a strip foundation with a ground bearing slab. Block and beam foundations are also fine but only really work where there is an external brick skin being added to allow for snorkels to ventilate below the block and beam. SIPs are very light loading compared to traditional blockwork so foundation spec can be reduced and savings made on materials and labour although ultimately it comes down to what local building control are happy to sign-off on.
You can see this detail in our SIPs Details PDF here.
Any conventional heating system can be used although SIPs are ideally suited to innovative and energy-efficient solutions. Your ventilation strategy will have a big impact on your heating decision, but we would generally advise installing a mechanical ventilation with heat recovery (MVHR) system to cut heat loss.
The OSB (Oriented Strand Board) skins and the foam core materials do have some degree of resistance to the spread of fire but to ensure that construction fully complies with building regulations, internal walls are usually lined with a 12mm fire-resistant plasterboard which can then achieve a 60-minute fire rating.
No. The SIP panel is a thermally-efficient airtight product that works best without services running through. We recommend the use of a counter batten to create a service void for electrical wiring and fixtures to be installed.
If required on external walls, they can be surface mounted and then boarded over. Internal walls are timber stud and services follow a standard installation. Posi-Joists allow easy installation between floors.
Our standard panels have a core of modified Expanded Polystyrene (EPS). EPS foam provides lower U-values than other types of foam and does not contain chlorofluorocarbons (CFCs), which could deplete the Earth’s ozone layer. The U-value of our panels is extremely stable so values remain constant in both hot and cold temperatures. In field testing, EPS has been shown to retain virtually all of its original thermal and physical properties over a number of decades.
Our ambition is to develop our own environmentally-friendly insulation. We’re currently busy connecting with the sector’s most innovative suppliers, on a search for one that shares our vision for more sustainable building methods and materials. To learn more about this ambitious project, please check our news page.
An Ecologic SIP build system provides a vast improvement on air tightness as compared with more traditional construction methods, therefore careful attention needs to be considered to the ventilation method to create and maintain a healthy living environment. The average family of four produces up to 18 litres of water vapour everyday through normal activities such as bathing, cooking, and even breathing
Healthy buildings usually require a full change of air every two hours (m³/m²hr), as indoor air can be up to ten times more polluted than outside air. Mechanical ventilation with heat recovery (MVHR) offers the best solution to providing adequate ventilation for a SIP house. MVHR Systems are designed to quietly operate 24 hours a day, continuously circulating fresh air through the structure while removing unwanted moisture and pollutants.
MVHR systems, in combination with the excellent insulating properties of a SIP structure, greatly improve the energy efficiency and ultimately reduce your carbon footprint.
In a typical application, moist, stale air is extracted from wet rooms (kitchens, bathrooms, utility rooms). The air passes through a high efficiency heat exchanger which extracts the heat from the stale air and transfers it to incoming fresh air. Then the pre-warmed drier fresh air is delivered to other rooms. Most heat exchanger systems can recover up to 90% of the heat in the outgoing air, saving energy and money on heating costs.
We’ve teamed up with ADM Systems, they are experts at installing ventilation systems and have been working with clients across the private and public sectors for over a decade.
For more information on the benefits and features of MVHR systems and the optimum size required for your building please contact ADM Systems.
This is certainly common in smaller garden room type buildings in SIPs and technically possible in a full scale house build also. SIP floors should always have a minimum of 50mm airflow gap below. The ground beneath SIP floor buildings should be graded with a permeable membrane and/or Type 1 MOT/gravel cover or alike. We also recommend treating the underside face of SIP floor panels with a bituminous primer prior to assembly.
Whilst we can’t say there will be no movement in the structure it will be to an absolute minimum. The fact that the panels are one laminated entity with two sheets of structural sheathing to both the inner and outer face means shrinkage is reduced when compared to an equivalent typical timber frame construction.
That said, this is dependent on moisture content during the time of installation, and how dry the product is kept/allowed to dry once the sips system has been installed. We check the moisture content of both the OSB and timber at key points throughout the build to ensure they are within the parameters set by our accreditors (Structural Timber Association) and general timber construction standards.
We are also installing metal webbed engineered joists, one of the main advantages of these joists is their lack of shrinkage post-construction.
You get best thermal performance by centering the window within the SIP insulation. The two key things are:
To make sure the thermal resistance through the insulation around the frame is high enough to avoid a cold bridge (you will achieve this as long as the front face of the frame is no further forward than the front face of the insulation within the SIP or if it is then an insulated cavity closer is installed around the projecting window frame). If the window is positioned at the outer edge of the SIPs opening this will mean that there is less risk of water/weather exposure to the reveal of the SIPs.
To make sure windows designated as escape windows can open to the required angle.
Yes, the brickwork would form the outer leaf with a minimum 50mm cavity separating it from the internal SIP wall leaf. The brickwork should be tied to the SIPs with wall ties which can be fixed anywhere into the SIPs (see pages 76 and 77 of the STA SIPs pocket guide) and Simpson do a wall tie specifically suited to masonry>SIPs https://www.strongtie.co.uk/en-UK/products/brick-to-timber-brick-to-sip-tie-bts
Yes, traditional style working chimneys can be integrated into a SIPs build. There are specific details and systems available for this purpose and we can work with your architect to ensure their design for this works with our SIPs install.
Specifically, Isokern have a range of highly heat-insulating pumice stone systems which are suitable for this purpose. https://www.schiedel.com/uk/products/pumice-system-chimneys/isokern-dm/
The blockwork we normally recommend is a Thermalite 7N block https://www.forterra.co.uk/product/thermalite-aircrete-hi-strength-7/ which has a better u-value than a standard dense concrete block. Typically one significant way of improving this junction is to run the top course in Marmox Thermoblocks which are 65mm thick https://www.marmox.co.uk/products/thermoblock