Many self-builders – perhaps even a majority, and especially those on a low budget – choose to build using subcontractors.
In some ways this is like learning to swim in the deep end: choosing to build without the backup of a builder and taking on a project that in most cases is way outside their normal life experience. Most are successful. Most experience a very steep learning curve that involves mistakes, delays and misunderstandings on site, which the repeat self-builder will make certain never happen again.
Learning the sequence of events on a building site is invaluable. Learning what each trade does and where their responsibilities begin and end is vital. And learning that the critical path in building can so easily be thrown off course – and how to get it back on track again – is essential.
Listing the tasks of each trade is one thing. But all but a very few overlap to some degree and it’s important to understand the grey areas between, which can be the responsibility of a builder but which, in their absence, often falls to the self-builder.
The Groundworker: What needs laying on?
- All necessary consents and permits must be sorted out
- Materials must be sourced and ordered. In particular, concrete suppliers must be geared up
- Water must be available with a hose to a butt. If the temporary supply isn’t yet on, you’ll need to chat up a friendly neighbour
- A lockup, site hut and WC on site
- Security fencing should be available
- If they are labour only, you’ll need to have lined up a digger and driver. You’ll also have to ascertain where ancillary plant, such as dumpers, pumps, shoring and mixers are coming from as, when and if they need them.
- If spoil is going off site you might rely on the tipper lorry driver knowing where to take it. Otherwise you’ll have to find out the nearest and quickest tip to avoid delays on site
Who do they work with?
They’re on site alone in the first instance, but:
- It’s as well to have a plumber and an electrician lined up for emergencies, plus they may be needed to plumb in standpipes and install temporary supplies and consumer units
- If they aren’t laying the blocks, you’ll need to have a bricklayer organised
What do they do on a standard house?
- Create entry into and clear site
- Lay hard base for access, deliveries and site storage
- Strip topsoil and store for reuse
- Set out house to suitably positioned profiles (this may be carried out by a surveyor/architect)
- Mark out centre line of the dig
- Excavate foundation trenches to indicated or required depth
- Load spoil into dumpers for on-site storage/load spoil into tipper lorries for disposal off site
- Clean and bottom out trenches
- Position level pegs to indicate top of concrete
- Pour and lay footings concrete
- Lay foundation blockwork to dpc level putting in cranked ventilators, necessary drainage exit lintels and/or sleeving for services (sometimes done by bricklayers)
- Level out subsoil in oversite
- Backfill trenches outside the building
- Fill cavities with lean-mix concrete
- Position floor beams on dpc
- Lay infill blocks in place
- Brush grout floor or:
- Fill and consolidate hardcore to oversite
- Sand blind hardcore
- Lay damp-proof membrane
- Position below-slab insulation
- Lay further damp-proof membrane
- Lay oversite concrete
- Excavate trenches for foul and surfacewater drainage
- Lay drainage runs on pea shingle bringing upstands to positions though oversite
- Haunch over all below-ground drainage in pea shingle
- Build all manholes
- Connect foul drainage to foul sewer/the boundary for road connection by others/install septic tank/cesspool/mini sewage treatment plant. Install and lay any weeper drainage or outlets
- Construct soakaways and connect surface water drains
- Backfill all drainage trenches
- Excavate all service trenches and backfill when supplies are laid
- Carry out specified and agreed hard and soft landscaping and fencing
- Lay driveways, pathways and patios to agreed specification
This is the first of the major trades. On a standard house there would be about two weeks’ work to oversite. They may then go away until the scaffolding is down before coming back to do the drains but, equally, on some sites, they may choose to stay and do these as work progresses. This work should take between one and two weeks. They are usually, but not necessarily, responsible for associated works such as fencing, landscaping and driveways, which are normally done during the last two weeks of the project.
What do they cost?
A ganger, or site foreman, costs approx. £100 per day, a semiskilled labourer £90 and a general labourer £80. In the Southeast, these rates may be up to 50% higher.
- Some groundworkers don’t lay blocks
- Some will do the ground floor beam and block floor but not intermediate floors