Crofton Beam Engines Crofton, Marlborough, Wilts SN8 3DW A branch of The Trust Registered Charity No. CC209206

The World’s oldest working still doing its The World’s oldest working beam engine still doing its original job original job

CROFTON EXTERNAL WEST WALL REPOINTING

WORKS SPECIFICATION EXTRACT

This document provides details of the materials, workmanship and general specification provided to those undertaking the external works to repoint the external face of the west wall to the engine house at .

Pump House West Wall Description

The west wall of the pump house is of solid brickwork construction with cement type pointing to clay handmade bricks laid in English bond with lime mortar to the core of the wall. The window openings are spanned with cambered brick arches consisting of one soldier course of bricks, have sills are of limestone and the reveals of which are rendered from the frames to the wall face where they finish flush.

The face of the wall is in a deteriorating condition where there is loss of the pointing, plant growth in the brick joints and loss of facing and integrity to some bricks.

MATERIALS & WORKMANSHIP

QUALITY OF MATERIALS a use new materials unless otherwise stated b certify to the CA, when required, that materials not of UK manufacture have been tested by and comply with the prescribed standards of a recognised authority and that replacements of spares can be obtained in the country of installation. c ensure that materials specified to conform to BS are clearly and indelibly marked with the reference specified. Where this is impracticable, the relevant advice/delivery notes must include the BS reference with which the materials are to comply. Provide certificate of compliance with BS when required by the CA. d obtain the whole quantity of any particular material or component required to complete the work from one manufacturer or obtain approval of any change in source of supply. Produce written evidence of sources of supply when requested by the CA

SPECIFICATION BY MANUFACTURER'S NAME: mention by name of any firm or proprietary item, in this specification or on the drawing(s), is to be taken as an indication of the quality, performance and workmanship required. Articles of equal quality, performance and workmanship for which replacements and spares are available in this country may be offered to the CA for approval. Alternatives to specified building components may be sought only from other equivalent and approved suppliers.

BRITISH BOARD OF AGREMÉNT CERTIFIED PRODUCTS: Where materials or articles are specified as Agreement Certified, they must be obtained from a manufacturer currently holding a certificate for that material or article. Where more than one manufacturer holds such a certificate, then the choice rests with the contractor.

SAMPLES: materials and products that the CA may desire to be subjected to tests and analysis, shall be made available by the contractor as and when directed.

DIMENSIONS AND TOLERANCES OF COMPONENTS a check dimensions of components following delivery to site and draw the CA's attention to any departure from specified manufacturing tolerances. b adjust the position of components and/or the size of the joints within their respective specified limits so that adverse results caused by an accumulation of individual acceptable tolerances are avoided. Where, in spite of such adjustment, adverse effects cannot be avoided, immediately inform the CA and seek his instructions.

MASONRY

MATERIALS

MATERIALS FOR MORTAR: a cement: to BS 12, BS 146, or BS 4027 and manufactured by a BSI Registered firm. b sand: to BS EN 13139 c hydrated lime powder and lime putty: to BS 890 d water: clean and un-contaminated. Obtain the CA’s approval for other than mains supply.

MORTAR DESIGNATIONS: Material Sheltered Exposed brickwork of moderate durability B1 – B2 C1 C2 A1–A2 B1 – B2 Brick of good durability Any groups A – B - C C3

MORTAR MIX PROPORTIONS: mix constituent materials in proportion by volume as tabled below for lime mortars Lime : Lime : Sand : Additive Hydraulic lime : Sand Coarse Stuff Lime : Sand Sand A1 1 : 4 B1 1 : 4 :½ brick dust C1 1 : 4 D1 1 : 6 A2 1 : 3 B2 1 : 3 :½ brick dust C2 1 : 3 D2 1 : 4 A4 1 : 2 C3 1 : 2½ D4 1 : 4

BRICKS: shall be equal in all respects with samples approved by the CA and all comply with EN 772 - 3 and BS EN 772 - 2 as applicable. a The use of chipped bricks or blocks will not be permitted in face work.. b type of brick: :clay brick of size to match existing c colour: to match existing d finish: to match existing e manufactured by: reputable brickworks as approved by the CA

MOVEMENT / PANEL JOINT SEALANT: precompressed acrylic impregnated foam sealant strip with minimum 80% compression a type: Compriband TP605 b manufactured by: Tremco illbruck Limited http://www.tremco-illbruck.co.uk

WORKMANSHIP

BRITISH STANDARD: comply with PD 6697: in respect of: a setting out b scaffolding c storage of materials on site d use of mortar e laying and jointing

CUTTING OR RAKING OUT TO EXISTING WORK: all cutting out or raking out of brick joints to existing work to be carried out carefully using hand tools to CA’s approval. Powered saw, disc cutting or mechanical chisel or similar devises will not be permitted. Care is to be taken at all times to maintain existing brick / stone arrisses and not to damage brick faces.

RE-POINTING: rake out joints to walls to a minimum depth of 20 mm or until firm lime mortar is encountered. Clean out joint and fill fully and evenly with mortar and finish with dressing or profile with mortar as specified in a continuous operation.

DAMAGED WORK: take down and bear the cost of rebuilding any brick/stone/blockwork damaged by frost or other adverse conditions or resulting from non-compliance with this specification.

MOVEMENT / PANEL JOINT SEALING: install precompressed sealing strip strictly in accordance with the manufacturer’s instructions. Ensure faces of joint are clean, dry and free from dust and other loose material.

MORTAR - BRITISH STANDARD: comply with BS PD 6697 in respect of a storage of materials on site b batching, mixing and use of mortar

SITE MOVEMENTS OF MORTAR: ensure that tracks or runs for wheeled containers are as smooth as possible.

SETTING TIME: use mortars containing cement within two hours of mixing. Discard unused mortar.

SAMPLE PANELS: prepare sample panels to PD 6697 for each type of facing brickwork, including jointing or pointing, stone dressings, and finishes and obtain approval from CA before proceeding. Panel/s to be protected and maintained for the duration of the works to act as a monitor for quality and appearance.

THE WORK DESCRIPTIONS

Notes

This work is to a property that is listed by Historic England as being grade 1, and so is considered to be of national importance. Therefore all works to it will be subject to inspection and oversight by inspectors from Historic England, County Council planning department as well as the CA. Funding for this project is also being made available by the Heritage Lottery Fund who have the right to inspect the progress and quality of the work at any time.

Brickwork General

When raking our joints to brickwork for repointing or cutting out defective bricks and other items care is to be taken to avoid loss of arrases / edges to bricks, chipping of faces, etc. No power tools, angle grinders, chase or mortar joint cutters are to be permitted for such work.

Mortar used for new, rebuilding or pointing is to be lime mortar and to fully match the original for colour, texture and joint finish as approved in advance by the CA. All materials, mixes and workmanship to be as part 2 of this specification.

Clean away on completion and leave brickwork and surrounding area in clean condition including removal of any spread of dust or similar

Brickwork Repointing

Carefully cut and rake out using hand tools all defective mortar and hard cement type mortar to a minimum depth of 15 mm or until firm lime mortar is encountered. Clean out mortar joints and leave ready to receive new pointing.

Repoint cleaned brick joints carefully with mortar properly and firmly packed into the full depth of the joint and finish with the approved appearance.

Replacement Bricks or Decorative Items

Individual bricks as specified within the work schedule that are missing or defective to be replicated with new matching colour, size and texture bricks or manufactured pieces to CA approval.

Carefully cut out defective item for full depth, take out and cart away. Clean cavity and leave ready to take new replacement replica item.

Ensure new items fully match the original and build in / fix replacements including all necessary mortar or other bedding for the full depth, finishing, pointing, etc. Ensure new items match the original and surrounding brickwork to replicate and blend fully with the existing.

Window Reveals

Carefully remove render to reveals of window openings and rake out mortar joints as described for walls generally.

Include for removing all applied sealants and caulking between window frames and brick surrounds as well as to underside of timber cill over stone sill.

Allow for stabilising brickwork to reveals of windows as necessary including underside of head arches. Include for packing large cavities with mortar as specified, but maintain gap between side of window box and inserted material as found generally to perimeter of joinery.

Insert Compriband recompressed sealant strip of appropriate form and size into gap all the way around between brickwork and stonework to side of window box and sill. Strip to be placed so that it is approximately 12 mm behind external face of timber. Allow to expand before filling joint.

Provide and fix all necessary rules and edges and remove on completion of rendering after adequate time for curing and without damaging new render.

Re-render reveals and underneath of head including all necessary build-up coats worked fully back into mortar joints to brickwork. Form even thickness to inside of all reveals and finish with smooth surface.

Form V shaped movement to render at junction with timber window frame / box 6 mm wide at top to allow access to caulk gap between joinery perimeter and brickwork.

Caulk joint between joinery perimeter and render and between timber sill and stone sill with sealant as this specification and finish with smooth angle joint between the two to shed water. Clean overspread from timber and stone surfaces and blend into render.

Flashing Redressing

Carefully ease, adjust and re-seat flashing between upstand and roof coverings. Remove all extraneous material from under flashing

Carefully rake out mortar joint to top of flashing where tucked into brickwork joint if found to be defective. Include for replacement wedges, etc to mortar joints.

Carefully redress lead to sit flat and evenly to upstand face and roof coverings without causing splits or tears. Include for new replacement leadwork where any parts are missing or defective and cannot be redressed.

Repoint mortar joints to lead flashing where tucked into brickwork and other adjacent areas where previously raked out in lime mortar.

Leave all in fully weather tight condition.

Engine House West Wall Works

The wall is to be repointed from the top of the flashings to the cafe roof valley gutter at the base to the main roof eaves at the head. This work is to continue around the north return and onto the north wall for three whole bricks and around the south return onto the south wall for one and half whole bricks. The wall is to be left with a unified appearance and in a fully weather resistant condition. Include for the removal of all hard cement and defective mortar, plant growth etc.

Defective bricks to be cut out and replaced where brick face has eroded or spalled back more than 15 mm from original face or where brick is severely cracked and / or fissured and / or structurally unsound as an individual unit.

Window reveals to be carefully stripped of hard cement type render and re-rendered completely to ensure proper weather protection is provided to the structure at all times. Paint new render only with Kiem or similar paint of colour to Employers choice when cured.