D Groundwork

D1 GROUND STABILISATION/DEWATERING
D11 Soil stabilisation
D19 Site clearance
D2 EXCAVATION/FILLING
D20 Excavating and filling
D21 Landfill capping
D3 PILING
D30 Piling
D31 Preformed concrete piling
D32 Steel piling
D33 Timber piling
D34 Plastic piling
D4 GROUND RETENTION
D41 Crib walls/Gabions/Reinforced earth
D5 UNDERPINNING
D50 Underpinning

D11 Soil stabilisation

CONSIDER:
• Cement Substitution, Aggregate replacement See E10.
• Addition of lime to soil to stabilise it providing a firm base for floor slab, road or paving construction.
• Using lime allows the process to be undone, cement is more permanent.
• Dynamic compaction allows improvement of sub-soil loadbearing capacity without the use of foundations.
• Dynamic compaction and vibration techniques with or without the addition of stone or recycled concrete into piling hole can provide piled construction without the piles, i.e. no new concrete.

AVOID:
• Injecting cement in grout form to stabilise ground.
• Using piles: precast or insitu concrete into ground.
• Excavation of subsoil.
• Disposal of subsoil.
• OP Cement and Concrete See E10.

D19 Site clearance

CONSIDER:
COMPOSTING:
• Setting up a composting area throughout the contract duration
• Separate grass, leaves, twig, wood,
• The period the contract runs is probably sufficient to compost down any surplus from site stripping, 3 months is normal composting time, longer in winter.
• Rake grass areas and add leaves to compost area
• Cut grass and add to separate compost area,
• Tree trimming, shrubs, hedges, etc. to be cleared, could be cut and/or grubbed up and added to composting
• Cut and Crush twig and wood, add grass to twig and wood
• Damaged turf or scraps can be added to composting area
• Add compost to topsoil, or add compost to subsoil to make topsoil.

WILD TURF:
• Before stripping grass and topsoil check wild flower and wild grass content of grass
• Grass or topsoil as a potentially valuable material especially if containing wild flowers or meadow grasses
• Old or neglected site’s biodiversity can be maintained, enhanced or put to use on or off site
• Grass turf with a mix of wild flowers and grasses may be offered for reuse off-site via an appropriate website
• Post notice on appropriate Website for potential sale of turf
• Collect seeds, sort, dry and store
• Cut and store turf on topsoil stockpile until ready for use or delivery/collection
• Surplus or damaged or inferior turf to be composted

TOPSOIL:
• Topsoil may have value on or off site ideally locally
• Strip back topsoil and limit size of stockpile, plant wild flowers to discourage weed uptake
• Consider laying turf over topsoil stockpiles

HARD PAVING:
• Recycle demolished building masonry as hardcore
• Recycle paving and hardcore on site in sub-bases to new pedestrian pavements
• Recycle granite sett paving found under tarmac

SUBSOIL:
• Excavated soil from foundations, basements, services and drains is a significant percentage of Waste leaving sites
• Excavated soil to be used on site,
• Spread subsoil over site and cover with topsoil
• Excavate and stockpile clay for use as puddled clay waterproofing to basements or ponds
• Using subsoil associated with part buried buildings as a thermal store over the summer to release heat to the building in the winter
• Add Insulation over the top of the soil and beyond to trap the heat, but don’t insulate the walls or the floor of the building to allow it to pass through into soil or into building
• Check on ground water flows over 12 month cycle as this can take the heat away
• Swimming pools and surround in ground can be used to store heat from summer over to the winter in the same way

AVOID:
• Exporting subsoil from site, use on site or make available to Employer for use on site
• Exporting topsoil from site, make available to Employer for use on site
• Exporting hardcore or paving from re-routed pavements to be grubbed up
• Importing topsoil from off site
• Importing hardcore from off site

D20 Excavating and filling

• 23.7 m tonnes (33% of 90 m. tonnes/year) of waste is soil including stones and rock and classed as ‘inert’.

RECYCLE:
• Demolition rubble: Concrete and masonry or road plannings as site fill, hardcore in many uses.
• Sewage turned into LESA Lightweight Expanded Sewage Aggregate for site fill, hardcore.

CONSIDER:
COMPOSTING:
• Setting up a composting area throughout the contract duration.
• Separate grass, leaves, twig, wood,
• The period the contract runs is probably sufficient to compost down any surplus from site stripping, 3 months is normal composting time, longer in winter.
• Rake grass areas and add leaves to compost area
• Cut grass and add to separate compost area,
• Tree trimming, shrubs, hedges, etc. to be cleared, could be cut and/or grubbed up and added to composting
• Cut and Crush twig and wood, add grass to twig and wood
• Damaged turf or scraps can be added to composting area
• Add compost to topsoil, or add compost to subsoil to make topsoil.

HARD PAVING:
• Recycle demolished building masonry as hardcore
• Recycle paving and hardcore on site in sub-bases to new pedestrian pavements
• Recycle granite sett paving found under tarmac

AVOID:
• Exporting subsoil from site, use on site or make available to Employer for use on site.
• Exporting topsoil from site, make available to Employer for use on site.
• Exporting hardcore or paving from re-routed pavements to be grubbed up.
• Importing topsoil from off site.
• Importing hardcore from off site .

D21 Landfill capping

CONSIDER:
• Collect methane and burn, collect methane and bottle for fuel.
• Duct harmless gases to roof level and release.
• Evacuation protocols and insurance issues where buildings cap landfill sites.

AVOID:
• Releasing methane to atmosphere, (Green house gas with 21 x CO₂ Global warming potential)
• Releasing harmful gases at building perimeters.
• Smokers shelters near the edge of buildings with gas venting to the perimeters.

D30 Piling

CONSIDER:
• Cement Substitution, Aggregate replacement See E10.
• Dynamic compaction and Dynamic vibration of recycled hardcore to form piles in soil.
• Recycled PVC piling, however if water passes through the site its use is suspect as polymer migration may release leechate into soil and then be carried by ground water to watercourses or water sources.

AVOID:
• Excavation of subsoil.
• Disposal of subsoi.l
• OP Cement and Concrete See E10 .

D31 Preformed concrete piling

CONSIDER:
• Cement Substitution, Aggregate replacement See E10.

AVOID:
• Excavation of subsoil.
• Disposal of subsoil.
• Use of cement and concrete See E10.
• Formwork for concrete .

D32 Steel piling

CONSIDER:
• Driven steel sheet piling, in preference to insitu concrete retaining walls.
• Screwed spiral anchor pile foundations, lightweight, avoid concrete, avoid excavation and disposal of subsoil.

AVOID:
• Excavation of subsoil.
• Disposal of subsoil.
• Use of cement and concrete See E10.

D33 Timber piling

CONSIDER:
• Recyled timber and 100% recycled timber products such as Woolock.

D34 Plastic piling

CONSIDER:
• Recycled PVC piling, however if water passes through the site its use is suspect as polymer migration may release leechate into soil and then be carried by ground water to watercourses or water sources.
• Other forms of plastic piling are appearing on the market, including that manufacturered from HPDE, which avoid the risks of using PVC.

D41 Crib Walls/Gabions/Reinforced Earth

CONSIDER:
• Timber infill: use trees cleared from site as logs.
• Use durable species, avoid preservative treatment.
• Gabions:
-Stone rubble, stone waste, crushed concrete, crushed brick.
-Stone rubble: modern interpretation or substitute for dry stone walling.
-Crushed Concrete for filling.
• Use existing subsoil as part of reinforced earth retaining walls.
• Use recycled masonry or concrete from any existing buildings or foundations .

AVOID:
• Using in external walls if not backed by airtight construction.
• Using in internal walls if not backed by airtight or acoustic construction.

D50 Underpinning

CONSIDER:
• There is a considerable industry sector in creating basements in existing buildings, particularly in London where high land values and small plots make extensions difficult.
• Basement can allow a building to be made more suitable for a growing family without having to move.
• Basements are useful places for thermal stores, rainwater harvesting, Compost toilet chambers, they can remain cool reducing the risk of bacteria in stored liquids.
• Use excavated soil as part of landscape features to avoid transporting subsoil to landfill.

AVOID:
• Excavation of subsoil.
• Disposal of subsoil.
• Use of cement and concrete See E10.
• Temporary formwork for concrete.