Section 02SUBSTRUCTURE

1. Trenches to be level, square and free from loose material and standing water.Steps and sides of foundations must be plumb.

2. All tree roots must be removed. Trench depths may vary – refer to NHBC Standards 4.2.

3. Ensure foundation depths take into consideration drainage depths within the vicinity of the plot.

4. All substructure, block/brickwork to be fully pointed and follow the relevant Standard Detail(s).

5. Do not breach cavities with block and beam. DPC must be present under beam ends.

6. Cap off all drainage to prevent debris falling in and creating blockages.

7. Telescopic vents must not be positioned within door openings or service meter locations whilst maintaining a maximum distance of 2m apart and 450mm from external corners.

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8. Aco drainage to be only installed as per the Standard Details, generally at front doors where level or sloping towards the property.

9. Finished ground level must be 150mm below DPC.

10. Shingle must be installed prior to the sub-structure drainage being laid.

11. When positioning manholes and inspection chambers take care to ensure these are set out within the property’s footpaths or landscaping. Avoid the manhole being half in, half out of the path. During construction, manholes must be protected and signed.

12. When constructing substructures ensure water services are built in with consideration given to frost protection.

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Clean and tidy foundation excavation.

Correct width bucket must be used for each trench. (Picture taken from outside trench.)

Foundation coordinates to be accurately plotted, and checked by the Engineer and Site Manager.

Well formed foundation steps.

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Trench blocks - external wall centred on strip foundation.

All substructure blockwork to be fully pointed.

Ensure poured strips are level.

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Garage foundation - Ensure well presented, tidy finish.

Neatly compacted granular fill ready for sand blinding/DPM, drainage capped off and sacrificial insulation to cavity.

Neatly installed pre-cast concrete beam.

Pile positioning and mesh. Note spacers to corners to ensure adequate cover.

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Block and beam slurry coated and sanded off.

All grouting to be completed prior to screed rails being built.

Ventilators need to be installed at maximum 2m centres, 450mm from ends and fully pointed.

For accurate results consider core drilling drainage penetrations in block and beam floors.

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Soil pipes capped during construction.

Use a brick or blockette to gauge (65mm-75mm) the toilet bowl outlet position if not dimensioned on the drawing.

Haunching to drainage to protect from damage when insufficient cover is available. (Note Lintel to be installed as low as possible and ground conditions/heave to be allowed for.)

Area between soil pipe and insulation filled with fire resistant expanding foam.

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Water pipe to be installed set off from blockwork. Insulation to be installed around pipe and duct to be gas sealed.

Openings to be sealed and vermin proof, ensure Rockwool or adequate expanding foam is installed. Note end caps in soil pipes during construction.

Lintels to be installed over drainage penetrations at lowest possible point.

150mm ducts to be built in external walls for drainage penetrations.

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Check to ensure Drain running away from house

Drain Test 1 - Testing draining prior to casting slab.

Drain Test 3 - Soil pipe neatly taped to insulation. (Cap to be replaced following drain test).

Drain Test 2 – Ensure pipework joined and falls correctly.

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Ensure reinforcement follows engineer’s design and has perimeter spacers installed.

Ensure party walls are square, in line and 100mm cavity for masonry.

Water pipes to be insulated and ducts to be gas sealed. All SVP’s to be protected during construction.

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DPM bedded into slab. Sacrificial insulation MUST always be removed.

Clear cavity, ready for Platinum Insulation to be installed. DPM bedded into slab. Blue bricks only to be used in line with site requirements.

Consistently sized and clean cavity, with fully pointed brick and blockwork. Must be checked prior to commencing superstructure.

Slab insulation taped and joints staggered.

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Keep externals tidy and complete in line with brickwork.

Straight, plumb and clean masonry below DPC.

Slab sanded off. Note artstone and manholes protected.

Drainage to be completed and correctly supported with correct falls. Avoiding siting drainage on hard spots, ensuring ground below is stable, and bedded on pea gravel.

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External rainwater drainage pipes must be finished at least 150mm below DPC.

Drainage location to avoid manholes being located half in, half out of the path.

Slabs must be cut neatly around external door cills. Drainage is only required if paving is level or sloping towards door. If paving slopes away a 10-18mm gap is acceptable.

Sub-structure drainage must belaid on pea gravel.

Telescopic vents must not be positioned within door openings, maintaining a maximum distance of 2m apart and 450mm from external corners.