We have recently carried out an in depth research on the advice given by many building industry professionals on the style and cost of a typical small scale residential extension.
It is striking that no one focuses on modern and cost efficient construction methods or ways for conservation of fuel and power during and post construction.
We are all experiencing rising electricity and fuel costs, increasing construction cost and shortage in construction industry staff and materials and the government or utilities companies for haven’t done enough to modernise and diversify construction market or introduce alternative range of renewable energy sources which could prevent this highly concerning situation.
For the above reasons Atelier 41 Architects have decided to show the benefits of the most underestimated and still rarely chosen systems that can address the above issues and make us think less about utility bills in the future.
Cost efficient methods to construct you home extension or a new build house:
SIPs - Structurally Insulated Panels
This construction system is growing in popularity as it offers prefabricated panels that can form walls and roofs with factory cut window and door openings. If the layout is properly designed a costly steelwork can be avoided and construction sped up. Furthermore, no steelwork means no special cranes or plants are required which are also becoming pricey these days.
Benefits of SIPs System
It is normally recommended that a trained contractor carries out the construction, but the installation is a very straightforward process hence for a smaller development it seems unnecessary.
The structural stability of panels allows to construct both single and two storey buildings and a high U-Value (Thermal Transmittance) of the insulation provides excellent thermal performance.
According to “Sips Eco Panels” a leader in the UK market of SIPs panel of 219mm thickness can provide a U -Value of 0.13W(M2K) when used as wall. It is worth noting that the above values exceed by 50% the requirements in Part L of the Approved Documents of the Building Regulations.
The system also allows for significant space saving due to a reduced thickness of the walls.
As the walls are much lighter than those built out of masonry it is also quite likely that foundations will be shallower and more cost effective.
Points to consider when using SIPs System
The system can be built by a general contractor.
The design has to be prepared and coordinated by a professional so that accurate drawings can be prepared specifying the location of all penetrations in the factory made panels to avoid unnecessary cutting or adjustments on site.
The system can be used with facing brick or stone façade as an external finishing layer.
It is most efficient to use the system when you are planning to clad the building with timber cladding, hanging tiles, zinc, metal, or copper cladding or simply render it over external grade plywood or fibre cement board.
It has certain size limitations but when it comes to domestic extensions it can be utilised for ample applications.
Using SIP’s panels with are sustainable and eco-friendly may contribute to increasing your chances of obtaining a planning permission.
Further information on SIPs systems and leading manufacturers
https://www.sips.uk.com/products/sip-panel
https://sips-panels.co.uk/residential/
Timber Frame Wall Construction
The method involves timber studs, wall and top plates creating a frame together with traditional roof structure made of joists or rafters. The timber structure is normally installed on concrete slab or short plinth out of engineering brick (may be a cavity wall). Atelier 41 Architects have recently designed a development of 10 new build houses in Essex using the above construction method and found out that only about 25% of all new buildings in the UK are built using this system although it offers a quick and easy construction, reduction of site waste and construction cost.
Benefits of Timber Frame System
Many of our clients have unnecessary reservations as to the timber frame construction.
Some of them claim the construction method is unstable or not well insulated, but the percentage of such houses is incredibly high (75%) in Scotland or in Scandinavia for that matter and one cannot argue these timber frame natural beauties would find so many enthusiasts if they were not sufficiently insulated.
With regard to the stability, timber is a very durable material that does have really good bending qualities that are to some extent required in the building industry.
One may say fireproofing might be an issue, but when properly treated and lined, timber can provide outstanding fire performance of up to 120min exceeding the requirements in Part B of the Approved Documents of the Building Regulations.
The reliable sources confirm that timber frame construction is about 30% quicker than traditional construction in brick and block.
All this considered the timber frame construction is an eco-friendly, speedy, and cost effective construction method that could especially be taken into consideration for single storey rear, side and wrap around house extension.
Points to consider when using Timber Frame System
The construction method can be built by a general contractor or if it is a small building in the garden, it can be treated as a DIY project.
Timber is most sustainable form of construction.
To prolong durability of timber, protect against fire spread, and prevent it from decay and insects, timber has to be treated, and you can buy it as pre-treated or alternatively do it yourself. A timber structure has a very few limitations and the highest building made almost entirely out of timber (called by some a plyscraper) is actually 18 storeys high.
Further information on Timber Frame and Guidance
ICF - Insulated Concrete Formwork System
The system may resemble Lego Building Blocks only made out of rigid insulation (mostly EPS - Expanded Polystyrene Foam) which are hollow core. The blocks are interlocking and laid without any mortar. The hollow part later receives a steel reinforcement and concrete core cast on site. The system offers range of typical blocks including special lintels over openings and it is also used in conjunction with similar insulated floor blocks that create a formwork for a reinforced concrete layer on top.
Benefits of ICF system
This construction method creates a well-insulated, watertight, acoustic, and fireproof building envelope that can reduce labour cost, simplify, and speed up construction process and reduce amount of steelwork required or site waste.
What is most important this building method can help achieve a passive house that essentially requires one tenth of the energy required for a standard house.
Thermohouse, Sunblock and Thermomur are leading companies that have successfully operated in the UK market for 20 years, are LABC Approved (Local Authority Building Control) and can offer appropriate certification from BBA (British Board of Agrement) or NSAO (Irish Agreement Board) which guarantees a durable, high quality and reliable product. Atelier 41 Architects designed three new build houses in Hadley Wood and Mill Hill using the Thermohouse and Sunblock construction methods back in 2014 and 2019.
The speed and quality of these new build developments exceeded the developers’ expectations, and we are sure we will be designing houses using similar techniques more and more in the future.
Points to consider when using ICF – Insulated Concrete Formwork
The building can be made watertight very quickly.
Normally an architect is required to closely cooperate with the system’s manufacturer and builder on site to ensure the manufacturer’s construction instructions are adhered to.
Also, regular architect’s inspections would be beneficial.
Further information on ICF – Insulated Concrete Formwork and Manufacturers
Summary
All the above systems are becoming more and more popular in the UK construction market due to reduced availability of the standard building materials.
They are highly sustainable and despite a common opinion do not require highly qualified workforce.
It is definitely worth considering them as it may directly contribute to the reduction of the construction and living cost.
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