Roofs and roofing
Building a house: where do you start and how do you plan each stage?
Start with the plot, the way you want to live and the budget for the whole project. These guide your choice of design, construction method and contractors. Early decisions affect the foundations, roof and insulation. Allow time for deliveries, inspections and materials to cure or dry. This reduces changes on site and helps you avoid ordering materials that do not work together. Check what can be built on the plot, access from the road and the conditions for connecting utilities. Measure the site and consider its slope and surroundings: these affect where the house can stand and how it is built. Investigating the ground helps determine suitable foundations. Before settling on a catalogue design, check that it suits the site.
In this article
What should you check before choosing a design?
Write a brief describing the rooms you need and how you intend to work, store things and park. Decide which spaces will be heated and which will serve as utility areas. A garage, a workshop and a carport have different requirements for the building envelope and services. A clear brief can save you from having to add floor space because something was missing from the first sketch.
How do you draw up a realistic budget?
Break the costs down into site preparation, design and documentation, structure, envelope, services and finishes. List utility connections, external works and transport separately. The price of the shell is only part of the cost of a house ready to move into. Make an allowance for known uncertainties rather than assuming every quotation will remain valid throughout the build.
Compare the cost of each system delivered and installed. Inexpensive roofing sheets without flashings and fixings do not make a complete roof. Insulation also needs a properly prepared substrate and suitable junction details. Ask each supplier to price the same revision of the design. Otherwise an apparent price difference may simply reflect a different scope of work.
Which decisions must be made before work starts?
Settle the structural layout, the roof form and the extent of the heated area. Agree on main service routes and openings. Decide how the house will be insulated, protected against moisture and ventilated. These decisions depend on one another. Changing one detail during installation can mean reopening work already completed elsewhere.
Before buying materials, check which procedures apply to the project and whether the documentation is complete. Requirements depend on the project and its circumstances. Agree who is responsible for design and who directs the work on site. Structural decisions need a project-specific assessment; advice from a supplier or experience from a different site is not enough on its own.
How can you coordinate deliveries with the work on site?
Establish the sequence of work and inspection dates, then adjust orders to actual progress. Long roofing sheets, sandwich panels and PIR insulation boards all need suitable storage. An early delivery can get in the way or expose materials to damage. A late one can leave trades waiting and delay the next stage.
Plan access for the delivery vehicle, the unloading area and how materials will reach their installation point. Check that the site has enough space and sufficiently firm ground. Measure the structure before ordering items cut to length. Preliminary quantities taken from drawings help with budgeting but do not always replace measurements on the completed structure.
Include temporary weather protection for the open roof in the programme. A weather forecast helps you plan but will not keep the interior dry. Agree on a protection method with the crew before work starts, especially if moisture-sensitive materials or services are already in place.
What matters when planning the roof and insulation?
Design the roof as a complete assembly, from the supporting structure to the flashings. For tile-effect steel roofing or T18 and T35 trapezoidal steel sheets, select supports, fixings and roof layers to match the design and product instructions. The low weight of the covering is only one factor. The structure must also carry snow, withstand wind and support any equipment specified.
Check that the insulation continues across junctions between walls, floors and roof slopes. PIR boards can reduce the thickness needed, provided the build-up and installation suit the job. Detail the airtight layer and water vapour control as well. An inspection before the lining goes on leaves time to correct defects that would be difficult to trace in an occupied house.
What should you record at the end of each stage?
Keep product documents, delivery records and inspection reports. Take photographs that identify the location, date and work shown. Mark service routes and important details before they are concealed. The record is useful for maintenance, future extensions or discussions about defects, even if the build itself goes smoothly.
Before the next stage, check that defects have been remedied and the substrate is ready. Keep the required curing and drying times even when the programme is tight. At final handover, collect operating manuals and the results of the specified tests. The handover should include instructions for using and maintaining the house as well as the keys.