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How long does a house extension take to build?


The lead time on manufacturing ranges from 4 – 8 weeks dependent upon how busy our unit is with orders and a time frame can be given ahead of order confirmation on request.

How much can you extend a house without planning permission?


Under permitted development, you can extend by the width of your house and project up to 3m on a town or semi-detached house under permitted development and without planning and up to 4m projection on a detached house.


However, with a 21 day proposed larger home application which we can undertake on your behalf you can double the projection being 6m on a semi-detached property and 8m on a detached property with a neighbor consultation scheme which writes to neighbors on each side of your property if no objection is received your extension will be granted within these sizes.  You can read more about this using the following link:-


How much does it cost to build an extension on a house?


Using our steel frame modular extension fully installed by our team you can expect to pay from £19,000.00 fully installed dependent upon the size of extension required, we can give you an estimated quotation free of charge by completing our online contact form, giving us the width and projection in metres.


Due to advances in modern construction technology, there are now more cutting-edge construction methods to consider when planning your extension. Below we have compared the traditional timber frame construction method to our state-of-the-art galvanised steel frame system.


Built on a robust pad and beam system, a galvanised steel framework is undeniably strong and durable and comes completely protected from environmental factors that can affect timber frames. Galvanised steel is inherently resistant to corrosion and its performance in both internal and external construction environments is both predictable and assured. Whilst timber is a highly durable material, the level of maintenance involved requires real commitment and unless cared for correctly, it can shrink, crack and warp through high and low temperatures and other adverse weather conditions. It also requires protection against termites and other insects.

Energy efficiency:

Steel frame buildings are comprised of metal columns and beams that are precision-punched or laser cut in factories. This prefabricated building method creates tight, energy-efficient building envelopes that decreases a building's energy use over its life cycle, with superior seals for windows and doors. Although timber is a natural insulator and can help reduce energy needs when it is used in windows, doors and floors, it is susceptible to human error. The energy efficiency of a wood frame home relies entirely on the skilled workmanship of carpenters to ensure precision fitting of the structure.


Environmental conservation has never been more crucial, and this is no less important in the construction industry. Widespread use of steel frame construction avoids the significant impact on the environment of deforestation. Additionally, galvanised steel systems are manufactured in a controlled factory setting, involving precision engineering which minimises wastage. Another factor to consider is that while energy intensive to create, steel is 100% recyclable. Timber is a renewable building material although care needs to be taken that it is grown quicker than it is used, which is often not the case. It is worth noting, that timber comes with imperfections that render some of the wood unusable, meaning wastage can be a significant problem. Speed of Construction: A steel frame system is significantly quicker to install than a traditional brick and mortar building, which makes it a very popular choice for many homeowners wishing to minimise disruption in their home. With 80% of the build happening off site, once on site the building is erected very quickly and takes a matter of days as opposed to an extended period of some months. A timber framework is assembled in a similar way to a steel framework system and therefore is also quicker to install than a traditional brick and mortar building.

Cost Considerations:

Given 80% of the build happens before the installation team gets to site, an upfront payment is required in order to secure your bespoke steel system. This can vary anywhere from 40-70% of the overall cost of the build. However, the speed in which the building can be constructed means total costs can be significantly lower than other, more time-intensive building methods. Accurately comparing costs on a like-for-like basis when looking at timber and steel framed houses is difficult, as there are a lot of variables that could alter the final cost of production. For instance, the cut of timber, the supplier and contractor used and whether the frame is pre-constructed or built from scratch will all bear an impact in the price of a timber-framed building. To find out more about our galvanised steel system and how this advanced building method could transform your home, click here.

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