Building your own Timber Frame House
Can I build my own DIY timber frame house
Well, most people can – although it is much more complicated that most people think and can be quite stressful. If you have good DIY skills and access to DIY building products and DIY building supplies, including timber frame panels and other building components, if this is the form of construction you choose, then you are off to a fairly good start. However, unless you are engaging an architect or very competent designer, you will also need significant knowledge of building design and the plethora of regulations that now impact on these.
We hope that these simple notes will help you to think about some of the basic questions while you are making up your mind which is the best way for you to self-build your own house.
Advice for Designing, Buying & Building a 'Kit' home
Today, you can buy a ‘kit’ house from many different sources in the UK and from abroad. The suppliers fall into a few different categories, for instance long established firms who have the capability to design, engineer, manufacture and build your home to your, and your architects. exacting design. Some of them have wider construction knowledge and experience, but many new entrants do not.
Then there are many ‘retailers’ of foreign made standard log cabin and other ‘frame’ homes. Unfortunately many are mainly sales people with little knowledge of how the building they offer are designed, made or assembled.
You can of course buy direct from a number of foreign house providers. They will invite you to visit their factory in, say Germany or Austria, talk with their designers and see how your house will be made. You can also buy from Canadian or Scandinavian firms who are highly competent in all aspects of their own countries requirements.
However, while they are very proficient and provide high quality products, they do tend to be quite expensive, especially when shipping and delivery costs are taken into account.
How to Choose a Panel Homes 'Kit' Supplier
How and which timber frame manufacturer should you choose?
Well, this will depend upon how knowledgeable you are about construction in the UK and the various codes and regulations that have to be observed. It’s a god idea to select a firm that has knowledge of these and can maybe do much, or all of the design for you.
Alternatively, choose a designer who really understands timber frame and how to get the best out of this, while also conforming to planning, building, health and safety and other regulations. These are no quite complicated and onerous.
Chalet Bungalow frame - Benfield ATT
Buying and Building a timber frame kit house yourself
Now you too can enjoy the many benefits of a timber frame home, just like Canadian, Scandinavian, Australian, American and millions of other people around the world do. In fact, in developed countries, timber framing accounts for around 75% of all new homes built today.
Prefab homes, green modular homes, pre-manufactured homes, prefabricated houses, pre-built homes, prefab cottages, factory built homes are all some of the terms used for what generically are termed ‘Kit’ homes. Most usually these are based around structural insulated building panels. These can also be used for floors and roofs, although building with SIPs panels (which are not exactly the same thing) may not be suitable for load bearing floors.
Winners of 'House Race' self-build TV programme - Benfield ATT
Appearance of a Timber Frame house
Over recent years, wooden house design, timber architecture in general, and the use of timber frame construction has found increasing favour with architects and other building designers. One of the reasons is that you can make your house look just the way you want it to just by your choice of claddings for the external walls.
For instance, if you want to evoke the appearance of, say, a traditional British fishing village, you might choose tile or slate hanging. If you prefer a rural barn style look then wide timber boards fixed onto the outside of the frame might fit the bill. Alternatively you might fancy a New England look, again using timber or composite boards, but maybe narrower and with a pre coloured pastel shade.
Of course, in the UK many major house building firms are now using timber frame construction methods to deliver the enhanced insulation required by the latest building regulations. Many of their homes are clad outside with bricks or render, or even a mixture with some other form of cladding, depending on the local vernacular. Indistinguishable in appearance from a full ‘brick and block’ house, you can make yours look just the same if you wish.
Private Development Bristol - Benfield ATT
Standard Wall Building Components
Factory made, engineered timber frame wall panels are ideal for house extensions as well as new build homes. These prefabricated walls are fast and relatively easy to assemble on site, especially insulated panel systems, meaning you can get the roof on in double quick time.
Since they are already ‘sheathed’ with OSB3 (a modern alternative to plywood) with a waterproof membrane on the outside, this lets you get working in the dry almost as soon as this building ‘shell’ or ‘envelope’ for your frame house plans is constructed. If it’s raining or snowing any external wall claddings, including brick or blockwork if this is what you choose for the outer ‘skin’, or leaf, can be left to be done when the weather is fine.
Timber frame infill panels or external cladding panels are also a popular construction component for steel, glulam and traditional open framed structures, with most of these structural timber frame components using rigid insulation board depending on the timber frame panel drawings / design.
Insulated Structural Wall Panels
Insulation is a key consideration in choosing what type of walls you want. The building regulations stipulate minimum ‘U’-values that must be achieved through the entire wall areas – which include windows and doors. They also stipulate what must be achieved through the floor and roof. These also take into account the ‘U’ value performance of any additional materials and components used for covering or cladding the outside and the inside of the walls.
Factory Insulated Structural timber frame - Benfield ATT
The types of insulation materials available include wood wool, rock wool, glass wool, cellulose (e.g. recycled paper), sprayed foams, and rigid foams. The insulating, or ‘U’-value, of these varies for each material, so the less this value is the thicker the wall required to meet the regulations. In turn this determines what size of structural element is needed, e.g. masonry, steel, or timber, and the type of insulation materials, e.g. polystyrene insulation, foam board insulation, etc.
Prefabricated Wall Panels
In most modern ‘kit’ houses and similar scale buildings it is the walls that carry the loads of the roof and floors down to the foundations. There are three main ways of doing this.
Timber Frame Panels
First, and most common, is a timber frame with a large panel of orientated strand board (OSB), a variant of plywood, fixed over the outer face. This provides ‘racking’ resistance to keep the panel square and upright. The thickness of the framing timbers can be whatever you want, but the smallest is generally 38mm x 89mm, more often used for garden offices and other amenity buildings. However, kit homes and flats up to 3 or 4 storeys can be built using this size of timber if supplementary insulation is added to meet regulatory requirements.
Frames can be made using either solid timber or ‘I’-beams (more usually used for joists). The ‘cells’ between the framing timbers can then be filled with whatever type of insulation you prefer. The thicker this material needs to be in, say, foam insulation panels, the thicker the timber needs to be to accommodate this.
The insulation can be applied on site, but for convenience, time saving, and reliability this is increasingly being done in the factory when the framed panel is being made. This form of insulated building panel construction then provides you with factory insulated timber frame panels.
Open cell wall panel 'kit' house Benfield ATT
Building with SIPS
Second, and becoming popular for owner built ‘kit’ homes, are Structurally Insulated Panels, or SIP’s. Like factory insulated panels these are generally made of two OSB3 ‘skins’ with a rigid foam core sandwiched between them. This foam can either be injected as a liquid foam which sticks to each skin as it solidifies, or provided as a preformed sheet board to which each skin is separately glued. Both processes are done under pressure to ensure that there is good adhesion between the skins and the foam core.
Most commonly this type of panel comes in thicknesses of 100mm and 180mm, but some manufacturers will supply up to 240mm thick SIP panels. Generally these are in a standard 1200mm x 2400mm size, but can be longer by special request.
SIP panel house under construction
If OSB is used for the SIP panel skins, this is usually 11mm or 15mm thick and generally the same on both sides. However, some manufacturers provide a hybrid with, say, 11mm on one side and 15mm on the other. The thickness is often related to the type and weight of cladding to be hung on the skin.
Solid Timber Wall Panels
Third is the use of solid timber wall elements. Although used fairly widely in mainland Europe and have been used in the UK for commercial and other buildings up to 11 storeys, so far they have only been trialled by a few architects and individual clients with special requirements for new build timber houses.
The solid timber is generally made up of cross laminated, or glulam timbers. These are small timber sections glued together to form truly solid wall elements that interlock together to form a continuous surface. Manufactured in varying thicknesses from 80mm to circa 240mm, they can be provided in very long lengths.
Prefabricated solid timber house
Other Timber Frame Panel Materials
External sheathing / skin materials can be of different types, like magnesium oxide board, or cementitious based boards. For timber framed panels this can even be tongues and grooved boarding. Internal insulating cores within SIP sandwiches can also be of other materials, like foamed glass, or EPS. Most usual for factory prefabricated stud wall insulation is PIR (Polyisocyanurate) or PUR (Polyurethane) foamed insulation either injected or in sheet form.
Insulated Wall Cladding Systems
Most professional building kits are built using either insulated timber frame panels, or SIP panels, since these are generally the most effective and efficient ways of providing the insulation levels required for the walls. If thin walls, like 100mm timber frame (38x89 framework + 9mm OSB), or 100mm SIP’s are used, then some supplementary means of insulation may be required.
Often the same or similar materials are used for adding this additional wall insulation either on the inside, or the outside of the panelised frame. Choice of these is likely to be determined by the final finish required, e.g. timber cladding, tile hanging, or brick skin on the outside, and plaster or tiled walls on the inside.
Solid timber walls (e.g. CLT, Glulam, log) will almost always need the addition of one of these types of insulation. This includes Log Homes which, while they may be acceptable in the countries where they are being exported from, are unlikely to meet UK Building Regulations without this.
Making Your Own Timber Frame Panels
It is, of course, possible for anyone to make timber frame panels – or possibly even SIP panels – themselves out of whatever materials they want. This can be done either on or off the building site with stud wall timber of the right structural strength grade and stud wall insulation.
Likewise it is possible to ‘stick build’ a similar structure out of lengths of timber and panel sheets on site. However, even though planning permission may not be required, practically all building works in the UK are subject to the Building Regulations, with materials and construction details being approved by the Building Control officer. Such approval usually requires verification that the walls and panels have been assembled or made to industry approved standards.
This means that unless whoever makes the panels, or stick builds the walls, has a recognised competency, the structure may not be accepted or approved – at least without possible extra costly inspections and/or other expense. For this reason, most architects, house designers and owner builders find it more convenient and less costly to use readymade insulated timber panels from an established, recognised manufacture, to build their plans.
There is also the likely future value and mortgagablity of a house that is an ‘Owner Build’ to consider.
Self-Build Timber Frame Kit Homes Cost
As with most things, the cost of the components for a kit home will depend on the type of building, how complicated the plans to which it is to be built are, the use to which it will be put, the performance standards required, and the amount and type of insulation to be used.
The materials and components for Insulation in construction are very expensive. For a basic timber frame structure they can be even more expensive than the structural frame itself, depending on the type and thickness of the insulation required.
"Which" self-build guide
Self-Build house kit prices also need to consider the question of waste building materials and waste components. Waste on construction sites is a huge concern for the industry as a whole, with considerable related costs, like those of separating hazardous wastes, providing skips, and transporting these to landfill. For these and other reasons, many people choose to self-build factory insulated timber frame house kits with either timber frame or SIP frame exterior wall panels from an established company to suit their bespoke plans.
Timber Frame Home Kits
The market for timber frame home kits – for houses, timber frame bungalows, flats and timber framed extensions has been, and is, growing rapidly. This is not only because of the convenience and ease with which such buildings can be erected, but also because of the cost and time savings possible.
Attracted by this growth, a number of overseas companies have appointed sales agents to sell their standard products in the UK. If you are considering one of these then you do need to make sure that it will conform to UK planning, building regulation and health & safety rules and regulations.
However, some UK manufacturers now offer standard design ‘kit homes’ that meet these regulatory requirements. In addition, some are prepared to take the designs prepared by architectural designers for ‘wet build’ brick and block masonry housed and convert these into timber frame kit components for you or your contractor to erect. Some also offer on-site assembly services to erect these for you. A few also offer architectural design services for your special bespoke home.
Self-Build 'Kit' House, Tongue, Scotland - Benfield ATT
Architects, house builders and contractors are also turning to timber frame construction as their preferred method of manufacture, taking advantage of the improved quality and reliability of delivery that off-site factory built components and building can bring to their businesses.
For people and firms proficient in the use of such components, it is possible to buy all the necessary services and supplies separately, e.g. technical design, structural engineering, timber frame, SIP Frame, or CLT frame manufacture, but this does require some special knowledge and expertise.
To ‘fill the gap’ for those looking for simplified and lower cost alternatives, Easy Timber Frame has now made a range of standard factory made components for wooden house kits for sale. These ‘tick all the boxes’ for fast, reliable, low energy insulated timber frame construction.
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