Eco Frame Build Options & Model Sketch Ups of Your Future Home
Understanding the full build process before proceeding is important. An architect will go through all the pros and cons of any eco build and the materials used. One of the most important factors to consider before beginning any self build project are the structural materials that will form the walls and structural integrity of the building itself not withstanding foundations also.
Why are these materials important? When considering an eco build you are most concerned with heat containment during the winter and cooling during the summer. You will inevitably come across the term U value. This directly correlates with the abilities of the materials to enable thermal transmittance. The lower the U value the better the insulating properties of the performing materials or group of materials will be.
This section deals with building your knowledge about the different materials which can be used as walls of your sustainable house and whether choosing a pre fabricated design, a pre cut frame built at a factory or a timber frame built on site in offering optimum eco efficiency but also pitted against cost and project time. Additionally you may not wish to have a timber frame at all and opt for a brick skin with structural insulated panels or an entirely different block work or rendering.
Each of the different architectural types offer a different U Value. When considering an Eco Home this is an important value to keep in mind. One of the most muddled aspects of home building is structure versus interior. It is, in our view, best to focus on the structural wall building and insulation thereof before being too concerned with the interior. Properly structured walls and roofs with the correct insulation will allow your home to breathe as well contain heat through better insulation.
Choosing A Build System In Line With U Value And Insulating Properties
That said, the usage of the walling build system will translate to how much plastering and interior trade work is required in the aftermath. With pre fabricated build systems, plastering tends not to be required and instead direct interior painting after installation. With an eco home you will need to navigate three aspects, cost of materials, delivery and build time and most notably, efficiency of the building’s eco skin.
There are several different build systems from which you can choose. It’s a common misconception that timber is the best eco material to utilise. While wood used throughout homes today is most definitely sourced from sustainable forests. A combination of both timber frame and a brick skin or simply a mix of concrete, insulated panels and concrete formwork with brick slips can equally provide a low finished wall U value..
If sustainability is one of your main concerns then building with a timber frame throughout is ideal and any pre fabricated timber frame can also be delivered with a fully completed timber façade in either horizontal or vertical panelling. Sourced from forests which are replenished using wood that lasts a century or longer they provide one of the lowest U value wall building materials. The two distinct build systems are Timber Frame Systems and Blockwork systems.
Timber Frame Systems With Brick And Additional Insulation
For the lowest U value using a timber frame you should consider insulation between and over the studs. Sandwiched between the plaster board and exterior brick work using plywood sheathing and softwood studs laid with foil facing insulation and a breathable membrane with flexible insulation such as a mineral wool and a vented cavity at the exterior, it is possible to achieve a finished wall U Value of 0.13w.
Other variations will see structural aspects insulated differently, in cavity rather than studs, an insulated cavity with multi foil insulation and a more complicated system of hung tile, render or timber cladding which offers the thinnest of exterior walling if space is an issue. Although the layers can be doubled up this will take on average an additional 25mm as opposed to the achievable and thinnest 238.5mm.
Blockwork can also be combined with a timber system using medium density blockwork and a vented cavity and vapour layer working as an air venting system. Alternatively stud and plasterboard insulation with a veneer of brickwork delivers your typical home with brick façade, if all out timber design is not the requisite feature. Remember also that any self build project can use any stone as per design or local authority plan requirements. Some projects have seen local barns torn down and bricks reused to compliment the locality and meet planning department guidelines.
You can achieve much lower U value walling if space is not a problem. Without a doubt, the more insulation you can fit in the better, though this comes at cost of land use as well as cost of materials. You can widen any gaps between blockwork cavities for additional insulation materials and studs and use more depth of insulation. Or a foil-faced breather membrane within a timber frame and on blockwork, simply use insulated plasterboard on the interior.
Blockwork Systems With Additional Insulation And Alternative Systems
- Within the blockwork system the lower the U value, the higher the expense is usually the rule of thumb, but if offsetting against future energy bills then a house that retains warmth in the Winter months will save far more over time and will most definitely save you money in the long term. Though any architect and contractor who offers such a blockwork system pertaining to a finished wall 0.10w U value will calculate these parameters so as to detail the benefits of such a system.
- A 350mm thin joint block work with brick which utilises extra wide cavities enables a more air circulative system, compacting that air between each material’s membrane for longer. Effectively using no timber frame but an interlocking system of brick, insulation, H+H Celcon jumbo blocks and dry lining you are producing one of the best energy efficient homes and wall brickwork systems on the market. Though at a cost of an additional 10% on average plus a third extra of wall depth.
- The range of alternative blockwork systems extends to amalgamations of regular blocks with extra wide cavities, Lightweight blockwork with conventional mineral wool insulation, partial fill cavities and concrete blockwork with thin joint blockwork. The options are varied however each come with their own combined finished wall U value.
- Some of which will recommend a render or cladding finish. Cellular clay blockwork and a polystyrene block system are also favourites of the industry though in keeping with eco home’s demands on U value, High performance structural pre-insulated panels and a High-performance I-beam system in the form of an engineered timber frame with brick façade can provide a U value as low as 0.13w.
Deciding Upon Cost Versus Build Time And Pre Cut Timber Frames
Whether you have decided upon a timber frame with brick façade, brick slips or a timber façade, there are only really two options with which to differentiate between when getting the timber structure in place with which to complete your home.
You can order, in tandem with site schedule and the laying of foundations, a pre fabricated timber frame. Depending on the source this may take up two twelve weeks.
These pre cut frames come with the additional benefit of including all materials or simply the frame alone. With or without windows and doors fitted beforehand, with all insulation and vapour membrane fitted throughout. Then it is simply a process of fitting all the walls and joints together on site. This vastly reduces time on site and labour costs and ensures the timber is water proof within a matter of days thanks to the assembly room being temperature monitored.
If you require brick slips or a brick facade, this can be laid after the pre cut frame or pre fabricated timber frame has been put into situ. If you wish to have a timber facade, normally the company that has built and supplied the pre cut timber frame can add the timber panelling during the assembly process. You will need to negotiate the different avenues when it comes to cost of pre fabrication, on site build time, labour and effectiveness of materials used to reach an optimum finished wall U value, against that of building on site.
If you discuss the varied options with your architect and building contractor, they may suggest that you can save thousands of pounds by building (stick build) the frame on site once the initial blockwork has begun to be laid. This may well differ from house to house, area labour costs and size of the plan.
Though it has been recorded that some stick builds have saved £20,000 over that of having a pre fabricated timber frame assembled and delivered. Which to any self build project is a huge saving but you need to offset the British weather, on site workmanship and of course your preference of interior walling or whether a pre fabricated solution delivered with no plastering required is sufficient.
Using An Architect To Create A Sketch Up Model Of The Timber Frame
As with every industry a wide scope of knowledge is very important when it comes to selecting an architect to see your project come into fruition. We are not being light hearted by recommending that you use the services of an architect who knows the value and use of every building material imaginable. this knowledge enables an architect to not only deliver under budget but provide for a highly efficient sustainable and eco efficient home.
There are several factors worth considering when you employ an architect to create a sketch up model of a timber frame. The first of which is that the architect is simply the start of the process. This day and age you can have any design of house you can dream of, though the same application of weight loading and structural density matter, the process is smooth but involves a few more people.
- An architect will produce a sketch up model of your desired home which can then be sent to an external party, normally the manufacturer of the timber frame. This will then be uploaded to computer – if not already completed this way by your enlisted architect.
- By using computer aided design software, the architect, yourselves, a licensed engineer and the manufacturer will ensure stress calculations and load bearing is all correct with project cost and time line factored in so you can decide whether a pre fabricated timber frame with or without pre assembled doors and windows is suitable for your location and project.
- Thanks to CAD software load bearings and joints and any configuration of timber design can be tested in a matter of seconds. So no matter how complicated your dream home appears to be, those tasked with engineering with wood can replicate most Sketch up models of frames from which they can pass on to factory for final manufacture a with the Pre cut frame built at factory before final delivery to you. Often without the need of external crane service as a manufacturer’s own load carrying HIAB crane can be used to lift sections into place.
Some helpful Do’s & Don’ts at this stage
When discussing your eco home project and self build dreams with your architect and future building contractor, note these particulars:
- An eco home should be concerned with finished wall U value but not at the expense of land usage. Remember an extra 100mm is applied to all wall depths, materials and joints and can increase cost.
- There is no doubt that pre fabricated timber frames and pre cut wood frames are quicker to assemble and reduce on site build time. However, have you investigated the cost savings with an on site stick build?
- There are many different materials which can be used to create your new eco home’s skeleton structure, cost each if possible and arrive at the best value cost wise and ecology wise. Don’t simply lump for the first that is recommended, ask for the pros and cons.
To find out more about the materials detailed in this article, to engage with an architect to arrive at a suitable eco home design or to start enquiring as to the best pre fabricated timber frame manufacturer for your location, get in touch by using the form below.