Build Process
Embarking upon a self-build house project can be bewildering if you are doing it for the first time. Here at HebHomes we want to demystify the process, to help our clients keep stress levels low. Articles in our guidance section will take you through the whole process step-by step.
Once you’ve found a suitable plot, secured the necessary statutory approvals (perhaps with our help), and secured finance for the project, you’ll be getting ready to start the process of actually building your flat pack home from HebHomes.
Here’s what that process will look like:
- Inform planners
Before work begins, you must check the conditions laid down by your planning department to ensure they have all been complied with. You should also inform the department when work will commence.
- Clear site
The first track will be to put in the track and to clear the site. If you have chosen to opt for a ‘supply only’ package from HebHomes, then this work will be completed by your main contractor.
- Dig trenches
Next, it’s time to set out the position of the house. You may want to ask your engineer to visit the site to check this has been done accurately as building in the wrong place, or at the wrong height, might upset a neighbour or the authorities. Once that is done the trenches are dug for the foundations.
- Build foundations
The concrete strip foundations are then poured according to the engineer’s drawings, and the underbuild of block – two leaves (layers) for a render and block house, one leaf for a timber clad house – are built to damp proof course (DPC) level. Hardcore, sand blinding and concrete slab is applied and poured to the engineer's specification. While this sets, a representative of HebHomes will visit the site to check the foundations are suitable; if there’s an issue, either the slab or the kit will need to be adjusted. We will also check the ground is suitable for laying down the kit and manoeuvring the telehandler around the site. Generally, 2m of compacted hardcore around the perimeter is required.
It is also normal practice to install the sewerage and drainage system while the foundations are being prepared.
- Erect to ‘wind and weathertight’
Next, the house kit itself arrives. Erection usually takes around seven working days for a team of four men but varies according to the size and complexity of the kit, and the time of year; who does it will depend on what type of HebHome package you have selected. It starts with the accurate fixing of the sole plates: timber runners onto which the SIP or CLT walls will be secured. After the walls and lintels, the metal web joists are bolted, followed by the waterproof first-floor chipboard flooring. The ridge is then craned into place and the roof panels carefully screwed, nailed and glued as per the engineer's fabrication drawings.
Internally, vapour control foil will be fitted and, externally, the thick protective membranes on the walls and roof. Non-load bearing walls will then be erected and finally windows installed. The house is now 'wind and weathertight' and ready to be inspected (and handed over, if you have chosen a ‘supply and erect’ package). But please note: in the wet and windy Scottish climate, there is still a risk of water ingress until the exterior claddings and silicons are complete.
- Finish the roof
While the scaffolding is up, the roof completion comes next: first with battening, and then profiled metal sheeting or slate. Roof lights, with flashings, are fitted at this stage while roofing is in progress.
- Joinery, plumbing and electrics
While the roofing work is going on, joinery can begin – with battening and framing to the walls internally. Once the basic internal roughing is in place, the electrician can start running wiring through the house, and the plumber follows. Underfloor heating pipes are run over floor insulation and set. The first elements of the heat recovery ventilation system are put in place, as well as the sound insulation.
At this stage the plasterboard can be fitted throughout, according to use: insulated plasterboard to the exterior walls, fire-resistant plasterboard behind the stove, water-resistant plasterboard in the bathrooms and thicker plasterboard to the ceilings to minimise sound transfer.
- The ‘second fix’
After the plasterboard has been fitted and the joints between boards taped and filled (or the walls fully plastered, as is common in England), the finishing work can begin. The joiner will be hanging doors, and adding skirting boards, architraves and so on. The plumber and electricians return to the site for the ‘second fix’ – fitting sinks and baths to their pipes, connecting electrical appliances, and so on. This is when complex elements such as the air source heat pump and the ventilation system are installed and connected. The kitchen must be installed, the floor laid, the tiling done, and bathroom furniture hung.
- External finish
While all this is going on inside the house, work will continue outside. Timber cladding or the outer leaf of block work will be completed. Rendering of blockwork is weather dependent. Guttering is fitted and connected to the drainage system. The site has never been busier!
- Finishing touches
The end is in sight! At this point, the decorators are meticulously painting the house and the rest of the site is being landscaped. Gravel is laid down on the road and the entrance tarmacked. Very soon you’ll have it all to yourself, and life in your new home can begin.
- Handover
Throughout the six to eight months it takes to build a house in rural areas, it is usual for the contract between client and contractor to be administered by an industry professional, such as a local architect or quantity surveyor. For a domestic house, this is usually a ‘minor works’ contract. The administrator’s job is to ensure their client only pays for work that has been properly carried out; to make sure, valuations take place every four weeks, and 5% of the value of the main contract is retained throughout the build period.
When the administrator decides that ‘practical completion’ has been reached, the keys can be handed over and half of the retained fee paid. At this point, you become responsible for insuring your own house.
If you’ve opted for a ‘complete turnkey’ package from HebHomes, we will organise NHBC warranties and for a completion certificate to be supplied by the council. If you have your own main contractor, the administrator will either provide certification on the house or have arranged a warranty.
- Defect period
Over the next year, any latent defects which become apparent should be recorded. They will be made good at the end of the defect period (or, if that would interfere with enjoyment of the house, rectified at the earliest opportunity). The final 2.5% retention is then paid.
For more information about the typical schedule for a construction project, visit our members’ area and look for the file entitled ‘Construction Programme’
The Project Manager during the build period is the main contractor. This means it is their job to coordinate the project, ensuring people and materials arrive on time and in the correct sequence so that the house is finished by the completion date in the contract.
It is the job of the Contract Administrator to ensure that the terms of the contract are met, and that money is paid for work properly carried out. They will also record any variations to the instructions, and decide on requests for time extensions or additional costs. Minor works contracts are fixed priced contracts and extra costs will only arise if the client instructs a variation (changes something), an item costs more than what was allowed within the contract (a provisional sum) or if the contractor is due extra money for an unexpected task (rock-breaking, for example).
Minor works contracts have provisions for liquidated damages. These are useful if a completion date by a certain time is essential – for example, if your house must be ready for letting. The figure inserted has to reflect actual loss and it should be anticipated that a contractor will normally increase his price to cover the risk if this clause is utilised.
If you have decided to coordinate the tradesmen yourself then you are effectively the main contractor. This means organising site provisions, insurances, materials and subcontractors. Substantial savings can be made in this way – but it is time consuming and is a difficult and stressful if you lack experience.
Any further questions? There’s more information in our guidance section, or don’t hesitate to get in touch with any inquiries about building our kit houses in the UK.
