Build Over Drainage Surveys

Pre & Post Conditional Drainage Surveys Explained

CCTV drainage surveys are becoming increasingly popular with Surveyors, engineers and architects.

From an architects point of view, the most important issues are Pre & Post Conditional drainage surveys for building extensions, this applies to both domestic and commercial properties but why are they so important?

The Pre-Conditional CCTV Survey

The Pre-Con survey is designed to identify the current drainage system at any property which is due to be extended, it will map the drainage layout, identify drainage system ownership be that water company, private or a combination of both. It will also help to determine the drain depth and flow direction plus identify pipe size, shape, diameter and its condition. These are all very important factors and this is considered to be critical information required by architects in the planning stage as a new design cannot be properly completed until this information has been obtained.

The new drainage system layout is typically designed once this information has been provided.

The Planning Meeting

In many cases the drainage surveyor will be asked to consult on the new system layout and design, this is often referred to as the planning meeting which normally takes place on site with all parties.

The Post-Conditional CCTV Survey

The Post conditional survey (Post-Con) is carried out once the new drainage system has been constructed, this is to ensure the new drainage system has been laid correctly by the building contractor and is fit for purpose. It will also ensure that the new system does not have any miss-connected drainage which can cause pollution to the connecting local watercourse i.e river, canal and stream s and that the Part H of the building regulations have been adhered to.

Drainage Surveys Require Due Diligence

Pre & Post conditional drainage surveys are part of the due diligence process of any building project and should never be overlooked.

Always ensure that you are using fully certified drainage surveyors to undertake this work in compliance with industry best practice and standards.

Here at Accelerated Drain Services we currently carry carryout between 700-800 of these surveys each year for a number of architects based in and around the London area. We are fully certified drainage surveyors and members of the NADC.

Build Over Drainage Survey Diagram

Frequently Asked Questions

Why are build-over drain surveys so important when extending your property?

These surveys will identify the depth, shape, direction and condition of the underground drainage

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Will I require consent from my local Water company ?

You do if the drains / sewers or part of the systems belongs to the water company, only a detailed survey will provide this critical data

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Who is responsible for obtaining this data ?

In some cases the architects will do this on the owners behalf but the responsibility remains with the property owner

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Who is responsible for obtaining this data ?

In some cases the architects will do this on the owners behalf but the responsibility remains with the property owner

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What is the cost of an average CCTV Build-Over drain survey

On a standard 3 bedroomed property the costs are around £340+vat, and an extra hour on site for each additional bedroom

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Should I use a Certified Drainage Surveyor ?

You should always use fully certified drainage contractors, never use unqualified contractors

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Does this also apply to commercial / industrial properties

Any and all building works on any property should include accurate drainage system data collected by CCTV surveying

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