Overview:

A ground-worker is a subcontractor who is employed by a developer to clear the site and lay the foundations for a property to be built. They will also usually install the drainage and services. This trade is usually paid on completion of the job rather than an hourly rate. Additionally, you can decide whether you pay for materials yourself or ask for the ground-workers to source (they will charge a sourcing fee on top of the material cost for this service). 

Ground-workers are normally there at both the start and completion of the build. This team will be responsible for following the plans to excavate the ground and dispose the soil. They will then concrete and build foundations up to slab level. When the property has been built, ground-workers will return to complete the finishing touches such as driveways and footpaths. 

Stages:

1. Clear site

Ground-workers will excavate the soil and arrange for lorries to come in and remove the excess to create a large hole. 

2. Peg out boundaries

Corners of the plot will be pegged out according to the measurements on the plans. Your local council planning department will provide a building inspector who will oversee the build to ensure you are adhering to the approved plans. They will check that you are laying the foundations in the correct place to stop you from building your property too close to a neighbours’ home. The plans have been approved right down to the centimetre so it is extremely important that you follow the rules from the beginning – this is the time to measure twice and act once!

Once the pegs are in, the edges of the site can be drawn so the foundation trenches can be dug.

3. Strip and Trench Filled Foundations 

Trench filled foundations are what we use for our builds as it minimises the amount of excavation needed. Also, the cost of labour is reduced because walls are no longer required to be built below ground level. Trench filled are preferred as they are narrow, (normally 150mm) dug to the necessary depth and filled with concrete.

The traditional foundation method was strip and this is where property walls were supported with blocks or bricks (normally 300mm thick) up to the damp proof course level (plastic barrier to prevent moisture rising from the ground into the home). This method is regularly used on sand or softer soil types such as marine clay. You should also use this option if the plot has a slope as the walls can be built to different heights to ensure it’s level.

Whichever foundation sort you choose (type of soil dependent) you also need to know how deep the trenches need to be dug. British Standard 8004 recommends that there should be a minimum depth of 1m (if large roots were nearby then it should be increased to 3M). As stated, these are the minimum requirements and don’t account for and issues. Such problems that could arise are large rocks, old water tank or a mine shaft. Unfortunately, you probably won’t be able to tell what is hiding under the ground before you purchase the site, so these are obstacles you will have to overcome at the time. Normally, one of the above will mean you will have to dig further down than anticipated which will add to the cost. One way to make the most of the bad situation is to use the increased depth to create a room underneath the property.

4. Services & Drainage

Your ground-workers will also be able to excavate the services trenches (electricity, water and gas) and then will backfill the soil when the pipes and cables have been laid. It is your responsibility to contact the relevant suppliers and arrange for them to access the site. 

Additionally, they will excavate the soil for the drainage pipes. As stated earlier, you have the option of buying the piping for the ground-workers or you can ask for them to take charge and you pay them for what they have used at the end of the project. 

5. Slab vs Block & Beam

There are usually two main options when choosing a floor for the foundations – slab or block and beam.

Slab is considered the less expensive option as the raw materials are cheaper, however there is more labour required to ensure it’s level. Also, you will have to wait for the slab to dry out. The area inside the footings is filled with compacted hardcore and sand. Concrete will then be poured onto this which when levelled out will form the slab. Dolly blocks will be laid around the edge of the slab and on top of this will sit the damp proof course. This is vital as it reduces the risk of damp getting into the walls of the property.

Block and beam floors are generally more expensive than a slab, however it’s far quicker as you won’t have to wait for the concrete to set. The block and beam floor is manufactured from concrete beams which will then sit on the footings. The gaps in between the beams are filled with foundation blocks and then this process is repeated until you have a flat slab. One issue to be aware of is that the beams have a built in curve to account for movement stress (to reduce the risk of cracking). This will make it more difficult to get the floor level as well as causing a bouncing feeling when walking on the internal level.

Disclaimer: The information in this website is for general guidance and is not legal advice. Specialist legal advice should be taken in relation to specific circumstances.