A selection of our most frequently asked questions
What are SIPs?
SIPs (Structural Insulated Panels) are made using a facing of OSB (oriented stranded board) with a filling of PUR (polyurethane) insulation. These panels provide a labour & material-saving alternative to the traditional timber frame or masonry construction. The insulation used in our panels is continuous and is not bridged by timber studs. This type of panel has been in use for over 50 years and they offer an energy efficient building system that substantially reduces on- site labour times & cost.
How much do SIPs cost?
What are the benefits of using SIPs?
SIPs have a number of different benefits when used instead of traditional construction methods: – High levels of thermal performance and air-tightness.
– Low levels of waste
– Off-site manufacture
– Fast on-site erection
– Reduced construction costs
– Meets current building standards
Do you deliver panels?
We will deliver to you, or you can collect from our factory.
What comes in a SIPs Kit?
We supply the following in a SIPs Kit:
1. 100mm SIP floor panels
2. 100mm SIP wall panels
3. 150mm SIP roof panels
4. All glue, screws & timber to complete the kit
5. Drawings (GAs for sign-off, production & assembly drawings
You will require:
1. Dig footings
2. Level in 600mm x 600mm x 50mm slabs
3. Breathable membrane to cover the entire base prior to laying the floor
4. Breathable membrane to wrap the walls
5. Windows & doors
6. Internal & external finishes, i.e. render, cedar cladding, weather boarding, brick finish or composite board
7. EPDM roof
8. Gutters & downpipes
9. Electrics, etc.
What are our lead times?
Our lead times:
• For a panel-only order it is 7-10 business days.
• For our Studios and Garden Rooms it is 4-6 weeks from point of first payment.
• For larger projects, i.e, Extensions, New Builds & Garages it will be around 6-8 weeks from point of first payment, dependent upon agreement of the drawings before production begins.
These times may be subject to change depending upon factors outside our control, in which case you will be notified of any changes.
What type of insulation is used in SIPs?
The insulation used in SIPs can vary, although we use PUR (polyurethane).
What can SIPs be used for?
SIPs can be used for houses, garages, garden studios, mobile homes, park homes, office, schools and much more besides.
Is Passive Housing possible with SIPs?
Yes. With a range of Structural Insulated Panel thicknesses and complimentary material combinations it is possible to build to a Passive House Standard ….. TODAY …… as long as you take on board the design criteria and incorporate a number of recommended technological changes to the way in which you design & build your house. 2016 is the government target for all new build houses to be ‘Zero Carbon’ rated. There is an established, tried-and-tested form of low energy housing– the Passive House – which the UK housing industry has been slow to adopt, until now.
One of the most important things about Passive Housing Technology is that it is nothing new – it has been around for over 100 years and is commonly used in Germany, Austria and Denmark. Another is that Passive Housing is a construction standard rather than a single method or style of building. Passive Housing can therefore be created using a variety of technologies, designs, materials and factors such as location, climate, materials, structure and ventilation all affect the Passive House you build.
Basically, Passive Houses are built to ensure a comfortable indoor climate in summer and winter, without using conventional heating systems. Passive solar design optimises the amount of energy derived directly from the sun by careful planning of buildings to collect the sun’s heat. As a result a Passive House only uses 10% of the energy a ‘normal’ home uses and only requires 15kWh/ (m2a) annually for space heating. By contrast, a traditional home uses around 180kWh/ (m2a) and most ordinary Scottish homes get only about 15% of their space heating from solar energy. Of course, there are questions about the quality and cost of Passive Houses. Can they really stay warm? Are they very much more expensive? Is the whole thing not too complicated?
The answer to the first question is ‘yes’- they really do stay warm – and cool. As to cost, the answer is ‘not much more’ – around 8% – 10% more expensive to build, but delivering savings of up to 40% on running costs. As to complexity, the answer is a resounding ‘no!’ While there are strict criteria for creating a Passive House, Passive House Technology depends largely on good building practice – and on good, common sense.
For example, the Passive approach suggests that it is not sensible to ventilate our modern houses by cutting holes in high spec doors and windows, ruining U values and creating drafts. Common practice in the UK – but surely not common sense! The Passive approach also requires that windows and doors are fitted well, minimising heat loss from drafts, thermal bridges and air leakage – common sense, but not common practice.
Passive House Technology addresses such issues specifically, requiring that all houses should have:
Thermally efficient windows and doors
An efficient heat recovery and ventilation system
Other key criteria for a Passive House include:
Well insulated walls (U-value 0.1-0.15 W/(m2K)
Compact building design (surface to area volume)
Minimal thermal bridging
Positioning of the house in relation to the sun and altitude
One of the most crucial factors in building a Passive House is the design and type of windows used. Glazed external surfaces have a major impact on the energy efficiency of a building envelope. Get the windows wrong- specification, location, design or fitting – and substantial unwanted heat transfer between the interior and exterior can follow. Get the windows right and they will help maintain the correct level of in-house comfort, winter and summer.
It is a fact that heat loss and gain in a well insulated home occurs mostly through the windows. In summer each square metre of glass in direct sun can allow as much heat in as would be produced by a single bar radiator.
In the winter months losses from a window can be ten or more times the losses through the same area of insulated wall. With a good passive design – large, south facing windows are typical- windows can trap warmth in winter and repel summer heat; and admit cooling breezes for warmer days and exclude cold winter winds on others. There are many choices of glazing for windows for a Passive House. Double or triple insulated glass is key to good thermal performance – for example, there are companies which can offer a U value as low as 0.6w/Mk2. Tinted or Toned Glass is also an option; it has a ‘sunglasses’ effect that reduces the solar radiation entering the house thus keeping it cool in the summer months.
The spacing between the glass is an important factor and the best thermal protection occurs when there is a 12mm to 15mm space. Solar control glass can also be used on the outer panel and a low emissivity panel for the inner, blocking radiation from getting in and heat loss from getting out.
So, we have the technology to create Passive Houses in the UK and with the Code for Sustainable Homes now being introduced, maybe, also the motive.
Do SIPs prevent Cold Bridging?
Structural Insulated Panels, or SIPs, are a lightweight modern building material, quick to erect and not affected by the usual problems of compression, racking, shrinkage and cold bridging, normally associated with Timber Frame and /or Masonry solutions.
SIPs start life as a fully insulated, cohesively bonded, composite panel which, when prepared as an off-site manufactured kit, only have their insulation reduced when some joins and panel edges require timber to be inserted, for connection to other panels or to form framing around openings, such as windows and doors. In other panel join areas, insulated splines are used and insulation is maintained.
Whilst timber is not as good an insulator as the foam in a SIP, it is a far better insulator than either metal or glass, for example, which conduct heat away immediately. These materials provide a cold bridge between the inside & outside of any building, whereas SIPs, with timber in a reduced number of locations provide, at worst, a differential of thermal performance in insulation terms.
Whilst cold bridging should always be avoided, or better still “designed out” of any building SIPs, with their impressive thermal performance & air tightness properties, are often used to “compensate’ for the ‘poor’ thermal performance of other materials, such as metal & glass.
In essence, SIPs do not suffer from cold bridging, only ‘some’ areas of lower thermal performance. Once this is understood, any energy assessor ‘should’ be able to accurately determine SAP rating at the design, construction or completion stages of any building. SIPs start life as a fully insulated, cohesively bonded, composite panel which, when prepared as an off-site manufactured kit, only have their insulation reduced when some joins and panel edges require timber to be inserted, for connection to other panels or to form framing around openings, such as windows and doors. In other panel join areas, insulated splines are used and insulation is maintained.
How far do we need to go on Air Tightness?
If you have missed it up to now, air-tightness is the major determining factor in new building design and is even infiltrating into the realms of building retro-fit. If we cannot keep the air we have paid through-the-nose to heat inside our buildings then we will be losing money hand over fist. The government psychologists are still arguing on whether they try and sell it as ‘losing money if you don’t’, or ‘saving money if you do’? At the end of any day it’s what’s more important to you, as the outcome is the same.
The design limit on air permeability for new dwellings remained static in the last re-working of the Building Regulations (2010) Approved Document L1A @ 10m3/(hr.m2) @ 50Pa. It didn’t move from the value set in 2006. But then neither did thermal elemental U-values that much. Their increase in 2010 belied the apparent regime that was initiated in 2006, and we were left wondering to a large extent, what are they thinking? Where are we going with this? The draft for 2014 provides a word on the street that will see a turnaround in fortunes again, depending of course what side of the fence you are promoting your fortunes from?
The industry gurus have been banging on about codes for sustainable homes (4, 5 & 6) and Passivhaus over the last year or two to such an extent that the minimum standards laid down in the current Building Regulations Approved Documents seem almost laughable, particularly when local planning authorities are flexing their muscles to insist on higher ‘sustainable code’ standards – just because they can. But because they can is good, – we must all do our part to transcend the current minimums, and do the best that is feasibly possible under given project constraints – costs and all.
But what difference does air tightness actually make? Those in the know about the standards ordained under Passivhaus at 0.6m3/hr.m2 and Enerphit @ 1.0m3/(hr.m2), with the code for sustainable homes coming in at anywhere between the Building Regulations maximum of 10.0 and the recommended good practice levels of between 3.0 and 5.0m3/(hr.m2).
Of course the CfSH procedures for calculation are a moveable feast orbiting around the Standard Assessment Procedure (SAP) so although air permeability is important in determining the Target and Dwelling Emission Rates (TER and DER) it is a figure that can be off-set by the very nature of how SAP works. This approach has its pros and cons, although to achieve the higher code level 6 (zero carbon) the likelihood is a figure of 1.0m3/ (h.m2) will be required. Still not Passivhaus though is it?
The ‘pro’ on Passivhaus is the immovable air permeability rate, and the high insulation levels and controlled ventilation will guarantee a warm stable environment. But Passivhaus is quite inflexible in design. The building orientation, strict window sizes / glazed areas – on specific building aspects will not be to everybody’s taste. The CfSH design criteria allows a far more traditional type appearance, and may appease Mr and Mrs Average in terms of kerb appeal. The ‘con’ being that thermal performance and post completion operating costs will inevitably not match Passivhaus.
But super air tightness and Passivhaus are not joined at the hip. We are not technically precluded from achieving ultra-low air permeability with a more traditional design approach that might suit the ‘volume’ house builders. The practicalities of achieving these levels may be another issue, and it is here that we must dig up the old chestnut concerning education of contractors in the importance of the smallest workmanship item that will never be seen usually concerning membranes, jointing tape and understanding cold bridging. – Perhaps another time.
Such a hybrid design may not provide Passivhaus thermal performance such that home owners will probably still require supplementary heating in winter. However, I would trade a supremely air tight building, with controlled ventilation for a little less thermal performance any day (if that was the choice). Think about heat leaving the building instantly with the air. – Keep the air inside the building and the heat will hang around for so much longer until it leaches through the building fabric – No contest.
How far do we need to go on air tightness? – We need to buy the most expensive ticket we can afford, to go as far as possible.
An extract from The Building Design Expert
How can we confidently future-proof our buildings?
It’s no secret, ever since the turn of our current century the Building Regulations (AD L) have constantly been updated to inspire the construction industry to innovate, ensuring that we can meet the ever growing demand to conserve fuel / energy. It was difficult to begin with, but with the wonderful gift of hindsight, we are able to look back to realise that the regulations have not been too onerous technically. They have in fact paid heed to the considerable cost implications that could have resulted, and they may well have been worse.
So every four years we have swallowed hard, joined hands and marched together in the spirited reduction to carbon emissions. The government’s relentless drive to meet previous government’s commitment made at Kyoto 1997 meant an upgrade of thinking, of use and implementation of technology, particularly on our new buildings, but definitely not forgetting the ones we already have.
You don’t have to look hard to know that we now have that ‘Tech’. In relative abundance. Because if we can’t do it via the swings, it will almost certainly work via the roundabouts, or maybe a combination of both. If it won’t work with double glazing, it will with ‘Triple and maybe a coating or two’. Perhaps throw in in a well considered renewable – You get the gist? It has all become very doable, and almost all of a sudden.
But what remains the ever constant make or break? You got it – Cost, with that capital ‘C’. It will always dictate what we do, and how we do it. Sprinkle in some sustainability to taste and the apparently straightforward task of ‘future-proofing’ our buildings just got very tricky.
Of course zero carbon is where we need to be, but practicality precludes us from using this yard stick as a true measure of three feet. When someone is brave enough to stick their heads above the parapet and define what is truly ‘zero carbon’ we can confidently stride forward with a yard to each step. But as long as we have legislative frameworks such as SAP, which incidentally should be an acronym for ‘Subjective Assessment Procedure’, allowing the like of home office facilities and cycle stores as key contributors in the Code for Sustainable Old Peoples Homes, is a mickey take of the highest order.
But SAP or no SAP, the difficulty financing a ‘future-proof’ budget means we have to choose how to spend it wisely and therefore effectively. Delivering the best combination of current tech., and addressing the building owners and users needs now, in anticipation of their needs in the future. Reading tea leaves was never quite my thing. Especially when they are wrapped in a soggy perforated paper bag. Does anyone do palms?
Buildings, or rather their components will wear out eventually if we let them. Developer: “…….these new windows should last us ten years”. Not quite true; there is no reason why windows should not last twenty or thirty years, maybe more. What was really meant was that the technology with which they were manufactured and installed should just about span ten years. By the end of that time window design should be so much more efficient, and better able to contribute to maintaining our building’s design temperatures, that replacement or refurbishment could be justified. But is ‘justified’ on technology alone enough? I know enough about my soggy tea bag and sweaty palms to predict that the associated costs just might stop this train on its tracks. We can increase the capex now, saving money on the risk that we won’t need to do it in the future. Step forward Mr Confident.
So what do we do? We can meet the current performance specification minimum, and ignore the future proof protagonists. Or, we can spend our way to the top of today’s pile in anticipation that it will be not too far away from the technological peak in a pre-determined number of years. Either way you will probably find that the old maxim applies: “Damned if you do. Damned if you don’t”.
So how can we confidently ‘Future Proof’ our buildings? – Tesco’s do not, unfortunately, do ‘BOGOF’ deals on high performance windows – not this week anyway! Until then it’s down to our best educated guess; not all of which will hit the nail squarely. The risk takers must prepare for some more bruised fingers.
An extract from The Building Design Expert
Are SIPs environmentally friendly?
Yes, by having less gaps and air leakages a property is created that requires less heating and also retains the heat better.
What heating system should I use in a SIPs building?
Any heating system is acceptable but it may need downsizing due to the air tightness and thermal efficiency of a SIPs building.
When were SIPs first used?
SIPs (Structural Insulated Panels) have been in use since the 1950’s in the United States, being used for both commercial and domestic building projects.
SIPs were first used in the United Kingdom in 1997 and their popularity has increased dramatically since 2009.