ISO 9001: Work Measurement, Dayworks & Weather Constraints

Measuring of Work

As part of the company’s QA procedures, all materials are measured after cutting to shape prior to welding. These figures are checked regularly against the area covered and form the basis of the final measurement.

Contract Price – Measured Work

Unless otherwise stated, the contract price is based on the surface area of material laid including materials in anchor trenches but excluding weld overlaps.

Contract Price – Fixed Prices

The price is based on the areas shown on the drawings and agreed prior to contract. Small variations in area will not incur extra costs.


Lining cannot be positioned at times when wind speed exceeds 20mph and lining cannot be welded in damp conditions (mist and rain) or when material temperature falls outside of range 0C to 30C. Therefore work rate can be severely affected by inclement weather. Whilst our costs of weather caused delay are for our account, contract time extensions will be claimed.

Site Conditions

All civil engineering work including dewatering is the responsibility of others unless otherwise agreed in writing. Should our works be delayed due to lack of suitable ground on which we can carry out installation works, the time lost due to these delays will be classed as standing time irrespective of weather conditions. The costs of such delay will be charged under our dayworks arrangements and extension of time claimed.


Any repairs or rework incurred due to damage caused by others will be carried out by our operatives and charged under our dayworks arrangements. Any extra civil engineering work required shall be carried out by others at no charge to Butyl Products Group.


We will programme the works in accordance with the original agreed schedule. Please advise us in writing of any programme changes. While we will endeavour to meet any schedule changes, we will normally require 10 working days notice of such changes.

Quality Assurance

It is a requirement of ISO 9001 that we receive full written instructions with the order a minimum of 2 weeks before any work is undertaken.

Working Week

Where possible we would wish to work 7 days per week on alternate weeks. This time is helpful in pulling back time lost to bad weather and reduces time lost travelling to / from site and is advantageous for the swift completion of the works.


The unloading of materials delivered to site shall be carried out by others (USUALLY TELEHANDLER / FORK TRUCK OR EXCAVATOR SUITABLE FOR THE MAX. LOAD WEIGHT BEING DELIVERED) at no cost to Butyl Products Group. Free assistance may be required for machinery and / or labour to assist in unrolling materials for cutting and site deployment.


Any extra works required resulting from site instruction changes, repairs and standing time will be charged as dayworks unless previously agreed otherwise. Site instructions are recorded on our ‘Confirmation of Verbal Instruction’ form and shall be signed by the main contractor / client and our Site Foreman (The form is produced in duplicate, one copy for site and one copy for our permanent records). Contractors own forms can be used in conjunction with Butyl Products Group own documentation.

Completion Period

Geomembrane works are very dependent on weather and site conditions, including ground and civils preparation normally being carried out by others. Any contract period agreed will be based on full production days of work.

Completion Certificate

A Completion Certificate will be issued on completion of the works. This should be signed by either the contractor or representative when they are satisfied that the works are complete and they are happy for us to leave the site.