If sewage pipes leaving the building have to be deeper than the top of the foundation concrete then they should also be ducted; they cannot be trapped within the concrete and must be able to move freely. These are a relatively new foundation solution consisting of slender, hollow steel shafts with a small number of steel helices (or screw threads) welded to them. The piles are screwed into the ground until they achieve sufficient friction to support the required load. Short bore piles are typically 2–3m long and can be reinforced with steel (Image credit: Homebuilding & Renovating)

building is spread evenly. For a post and beam structure, the piles or groups of piles are capped with a concrete pad. Screw Pile Foundations

Using rigid insulation and plaster

If the chalk is soft it will need to be excavated until firm chalk is reached. Chalk soils can be prone to erosion, so be wary of the possible presence of hollows or caves. The first 900-1,200mm layer of clay is subject to movement due to expansion and shrinkage from seasonal variation in moisture content, so it is generally necessary to excavate foundations to a depth where the amount of moisture present remains stable. In this practical, I’ll be focusing on a few methods you can use to construct some of these prototypes. For best results, I’ll be using materials suitable for scribing; a harbour wall made from rigid insulation and plaster (with another using DAS air-drying clay), an ashlar arch and various rubble walls made from styrofoam, and finally, a dry stone wall made out of more air-drying clay. Please note; as the painting technique I’ll be using will be similar for every practical, I shall share this at the very end. WHAT YOU NEED Local planning authorities will often allow structures to be built around trees within a root protection area on the proviso that the structures are supported by screw piles.

The capping stones feature a slope either side of a raised and rounded middle point. On a length of styrofoam 7mm wide, mark two parallel lines in the centre 1mm apart. Using a flat file, form slopes on either side.The raised section that’s left canbe rounded off with more light filing. Cut to the lengths required, then glue them onto the parapet using PVA. Michael is Homebuilding & Renovating's Director of Content, Vice Chair of the self build industry body, the National Custom and Self Build Association ( NaCSBA), presenter of multiple property TV shows and author of Renovating for Profit(Ebury).He also runs an architectural and interior design practice, offering design and project management services. He is one of the country's leading property experts and has undertaken over 30 building projects including two self-builds and the renovation of a Grade-II listed farmhouse. If the water table is high (for instance if the gravel is submerged), the bearing capacity will be halved, so it’s important to keep the foundations as high as possible. A shallow, reinforced, wide strip foundation may be suitable. Sand holds together reasonably well when damp, compacted and uniform, but trenches may collapse and so sheet piling is often used to retain the ground in trenches until the concrete is poured. Diagrams of strip foundations (left) and trenchfill foundations (Image credit: Homebuilding & Renovating)A reinforced suspended concrete floor slab, or a reinforced concrete ring beam, is then cast over the top of the piles, linking them all together so that the load of the

This can be a cost-effective way of building on sloping ground too, as the steel piles can be left above ground and linked together with tension wires or rods, and topped with a steel ringbeam or grillage to build from. Factors to Consider What Might Affect my Choice of Foundation System? Electricity and gas don’t usually need to be ducted or installed at this point as they are normally surface mounted. Finally, the building and warranty inspectors will have to approve the excavated foundations prior to any concrete being poured. Approved Document A of the Building Regulations (England and Wales) defines the minimum widths for strip footings based on the type of ground and loadbearing wall. The painting technique for the dry stone wall is slightly different from the rest. To ensure the paint reaches the crevices, spray a fine mist of water, then apply a very weak dark grey wash. Next, apply a slightly watery colour that matches the prototype stone in its un-weathered freshly-cut state. Finally, add additional dark grey washes as necessary, along with dry-brushed yellowy-green ‘lichen’ spots.

block paving

The standard foundation solution in most parts of the UK is the strip foundation, also known as strip footings. To cover the entire quay, I use household filler/plaster as it’s cheap, available in large quantities, and you can make it to the viscosity desired by varying the amount of water in the mix. Apply a thin layer of PVA to the quay walls, followed by a generous coating of plaster. Once left to harden (which can be up to 48 hours), sand the plaster until the required smoothness is achieved. The process of making stone walls using styrofoam is very similar, but there is no need for plaster, nor to scribe any joints; the pressure from the mechanical pencil on the soft foam while marking the courses will achieve the same result. As such, the Styrofoam rubble walls on the diorama (the ruined barn shown here, and the retaining walls) don't require further explanation, but the construction of the ashlar arch certainly does… There are three types of clay in the UK, classified by their plasticity, which is how much their volume can change due to their water content.