From Ministry of Water DCOM Manual

1 Timber and glazing

1.1 Scope

This Specification covers the requirements for, but is not limited to, all carpentry, joinery and glazing works.

1.2 Timber

1.2.1 General

A high standard of workmanship and materials shall be achieved in the works. The completed installations shall be durable, well finished, complimentary to the works and designed and constructed to achieve a service life of at least 25 years. Workmen employed in the manufacture and installation of the timberwork shall be experienced cabinet makers.

1.2.2 Materials

Timber shall be of best quality, sound, in good condition, reasonably free from shakes, and free from loose dead knots, insect attack, decay, twisting and warping. Timber shall be properly seasoned to suit the purpose for width it is intended as shown in DIN 4074. Only knots with characteristics similar to those detailed in DIN 4074 will generally be allowed. Where timber is described as "Selected1 it shall be free from knots.

1.2.3 Soft Wood

Soft wood shall be as follows:
• Redwood, specially selected from the best unsorted and joinery quality.
• Douglas fir or selected merchantable quality or better.

1.2.4 Hardwood

Hardwoods shall be selected and of the best quality; it shall be particularly checked for infestation by pinhole borers. Selected Iroko hardwood shall comply with DIN 4074, Grade IA.

1.2.5 Plywood

All plywood shall be approved by the Engineer and shall comply with the requirements of DIN 68705 and bonded to type AW 100. Grade FU I/Il or TI I/Il where varnished. Grade FU Il/Il or TI Il/Il elsewhere. Plywood and face veneers shall be free from end joints (including joints in veneers), overlaps in core veneers, dead knots, patches and plugs, open defects, depressions due to defect in cure, insect attack, fungal attack, and from discoloration differing from that normally associated with species. Face veneers require approval by the Engineer and shall be hard and durable and shall be capable of being finished to a smooth surface. Face veneers shall closely match the general joinery timber supplied and shall be applied to one or more sides as required.

1.2.6 Fiberboard

Fiberboard shall be in accordance with DIN 68750 (insulating board), type HFD.

1.2.7 Hardboard

Hardboard shall be in accordance with DIN 68750 (standard hardboard), type HFH.

1.2.8 Chipboard

Chipboard or materials incorporating chipboard elements shall not be used in the works without the express permission in writing of the Engineer. Where authorized, it shall be medium density wood particle board complying with DIN 68762, produced in factories by an approved process. Veneered chipboard, where used, shall be faced at factory with hardboard veneer (minimum 1 mm thickness). Where work has only one visible face, the rear (invisible) face shall have an approved balancing system. Veneers shall be carefully chosen and applied so as to present a good appearance. Choice of veneer shall be at the discretion of the Engineer. Full sheets shall have edges lipped with matching hardwood fillets. The fillets shall cover the full thickness of the sheet, and shall have a minimum thickness of 6 mm.

1.2.9 Melamine

Laminate shall be high pressure laminated sheets with a white suede or matt finish, with melamine resin surface, manufactured to DIN 68751 with a resistance to surface spread of flame in accordance with DIN 16926 grade AF. Laminate adhesives shall be selected, stored and applied in accordance with the recommendations of the laminate manufacturers.

1.2.10 Samples

Before commencing work, the Contractor shall submit samples of all types of timber to be used for the approval of the Engineer. Timber, or carpentry and joinery units of which the material on delivery to the site does not conform to the standard of approved samples will be rejected and replaced by the Contractor at his own expense.

1.2.11 Miscellaneous Material

Screws shall comply with DIN 95, DIN 96 and DIN 97. Timber connectors, where used, shall be two single-sided toothed plate (round or square) for demountable joints or one double sided toothed plate (round or square) for permanent joints in accordance with DIN Fixings to walls and floors and ceilings shall be carried out by the following means:
• Approved patent fibre or purpose made filling plugs fixed in accordance with manufacturer's instruction;
• Approved parallel expanding anchors;
• Hardwood plugs cut on the twist, providing the structure is approved as sufficient to take the plugs. Soft wood plugs shall not be used.

1.2.12 Ironmongery

The Contractor shall provide all necessary ironmongery including matching screws, bolts, plugs and other fixings. The use of nails for fixing ironmongery will not be permitted. Ironmongery shall be of the best quality and to the approval of the Engineer and, unless otherwise specified, shall be solid brass. The Contractor will be required to submit samples of all items of ironmongery (including hinges) for approval. All fittings shall be removed before starting any painting operation and shall be refixed in place after all painting works are completed and approved by the Engineer.

1.2.13 Selected Timber

Timber described as "selected" shall be selected and kept clean for polishing, varnishing, staining or oiling and prices shall include for finishing by hand with fine glass paper and for carefully matching adjacent pieces of timber to the same colour and character. Staining of timber will only be permitted as an integral part of the surface finishing process and if carried out by a fully trained operative.

1.2.14 Protection of Soft Wood

All soft wood incorporated in the works or delivered to the site shall be treated in accordance to DIN 68800 by means of double vacuum impregnation after final machining, but before assembly. Where cutting or boring after treatment is essential, two coats of the preservative medium shall be liberally applied to the cut surfaces. Where the preservative leaves visible evidence of treatment, it shall be suitable to receive the specified painting or staining. Where the preservative leaves no visible signs of treatment, a chemical tracer shall be incorporated in the preservative and a spray reagent applied by the preservative manufacturer as a ready means of identifying treated timber from untreated timber on site. The treatment shall be applied only to the fully machined components which in all cases shall have a moisture content of less than 16 %. Drying out time shall be as recommended by the supplier of the preservative fluid and the equipment. A certificate in quadruplicate stating that the required preservative treatment has been carried out shall accompany the consignment of joinery on the site and shall be handed over to the Engineer.

1.2.15 Moisture Content of Timber

All timber shall be seasoned. The moisture content of the timber during transit, storage and on site shall be about 25 % and shall be maintained until the works are commissioned. Prior to transportation all timber shall be polythene wrapped. On arrival to store or site, the polythene shall be removed and timber close-stacked on level bearers or suitable racks spaced to allow circulation of air and protected against water, dirt, decay, insect attack, soil and other deleterious matters. The Contractor shall take all necessary steps to preserve the timber in best quality condition and at the required moisture content. Timber for internal use shall be stored on site under dry and warm conditions similar to those of the finished building and for external use shall be stored under cover and protected from sun and rain.

1.2.16 Wet-Check Meter

The Contractor shall use an approved wet-check mois¬ture meter to monitor the timber.

1.2.17 Dimensions

All timber is to be sawn, planed, drilled or otherwise machined or worked to the correct sized and shapes shown on the drawings or as specified. Where the "nominal" dimensions are stated for wrought timber, an allowance of 3 mm shall be permitted for each wrought surface. The full size drawings shall be held to show the "actual" dimensions.

1.2.18 Exposed Faces

All timber that is to be exposed in the finished surfaces of the work shall be wrought on the appropriate faces, unless otherwise specified.

1.2.19 Natural Finish

When natural finish or finish for staining, clear polishing or varnishing is required, the timber in adjacent pieces shall be matched, uniform, and symmetrical in colour and grain.

1.2.20 Shrinkage

The arrangement, jointing and fixing of all joinery works shall be such that shrinkage in any part and in any direction shall not impair the strength and appearance of the finished work, and shall not cause damage to contiguous materials or structures.

1.2.21 Tolerance

Reasonable tolerance shall be provided at all connections between joinery works and the building carcass, whether of masonry frame construction, so that any irregularities, settlements or other movements shall be adequately compensated.

1.2.22 Fabrication

The cabinet maker shall perform all necessary mortising, tenoning, grooving, matching, tonguing, housing, rebating, and all other works necessary for correct jointing. He shall also provide all metal plates, screws, and other fixings that may be specified or that may be necessary for the proper execution of the works and shall also carry out all works necessary for the proper construction of all framings, linings, etc., and for their support and fixing in the works. No nails shall be used to assemble or fix hardwood, major supports, or ironmongery. Screws used in exposed locations and/or for hardwood work shall be brass and complete with brass surrounds.

1.2.23 Joints

The joinery shall be constructed exactly as shown on the approved drawings. All joints shall be the recognized forms of joints for each position. The joints shall be made so as to comply with DIN 1052. Loose joints are to be used where provision must be made for shrinkage or other movements acting other than in the direction of stresses of fixing or loading. Glued joints shall be used where provision need not be made for shrinkage or other movements in the connections, and where sealed joints are required. All glued joints shall be cross-tongued or otherwise reinforced. All nails, sprigs, etc., are to be punched and puttied. Surfaces in contact shall have a good sawn or planed finish. All cutting edges of tools are to be sharp to avoid burnishing. The surface of plywood to be glued shall be lightly dressed with sand or glass paper. The sand or glass paper must not be allowed to clog and cause burnishing. Members in construction to be joined by gluing are to be of similar size and shape. All surface to be glued shall be kept clean, free from dirt, sawdust, oil and any other contamination. Adequate pressure shall be applied to glued joints to ensure intimate contact and maintained whilst the glue is setting. All joints shall be flush, without gaps or imperfections. Mixing, application and setting conditions should be in accordance with the glue maker's instructions.

1.2.24 Adhesives

Adhesives for joints in non-load bearing internal work and for joints in work where the moisture content is always less than 16 %, organic glues or casein may be used. For work under damp conditions (moisture content normally 20 % or more or conditions liable to fungal attack) resin type adhesives are to be used.

1.2.25 Mouldings

All moulded work shall be accurately worked to the full-size details required. All mouldings shall be worked on the solid, except where otherwise specified.

1.2.26 Bendwork

Where bending is specified, the work is to be performed by saw-kerfing, keying, backing-a-veneer, laminating or steaming, and shall be carried out to the satisfaction of the Engineer.

1.2.27 Circular Work

When circular work is specified, it shall be built up with an appropriate number of pieces cut to the required shapes. The pieces shall be put together in two (or three) thicknesses so that joints are staggered and shall be secured with oak keys and wedges or with oak pins (whichever is more appropriate).

1.2.28 Veneering

Veneering shall be carried out in an approved manner, and to the entire satisfaction of the Engineer.

1.2.29 Scribing

All skirtings, architraves, plates and other joinery works shall be accurately scribed to fit the contour of any irregular surface against which they may be required to form a close butt connection.

1.2.30 Capillarity

The Contractor shall take all reasonable measures to check or prevent capillary penetration of water in the joints and open connections of external work, and in all other positions where timber may be exposed to water.

1.2.31 Weathering

All weathering surfaces, throatings, grooves and joints etc., and all open connections in external work shall be properly executed, and shall obtain good degree of weather resistance.

1.2.32 Finishing

All wrought surfaces shall be finished with a glass papered or scraped surface for decorations as required.

1.2.33 Hardwood Work Fixings

Fixings shall be by jointing to other timber (glued) or by means of brass screws with countersunk heads to proprietary plugs. Where work is face screwed, heads of screws shall finish not less than 6 mm below the surface and be covered with round hardwood pellets of appropriate thickness. Pellets shall be chosen and fixed so as to match colour and pattern of grain so far as is practical. Nailing will not be permitted. Sections shall be neatly and accurately cut with fine toothed saws.

1.2.34 Priming

All joinery which is to be painted shall be delivered to site unpainted and shall be primed on site immedi-ately after the Engineer's inspection and acceptance and before fixing.

1.2.35 Accuracy

the finished tolerances for the work shall be stated on the drawings and approved by the Engineer. All joints, arises, recesses, etc., shall be plumb, true and square. All units and members shall be installed such that they are truly plumb or horizontal.

1.2.36 Defective Work

All defective materials, workmanship or timber that is defaced or that splits, shrinks or warps excessively shall be removed and replaced, including any ancillary works affected.

1.2.37 Clearing Up

The Contractor shall clean out all shavings, cut ends and other timber waste from all parts of the building before coverings or infillings are constructed. All waste and rubbish is to be destroyed or removed.

1.2.38 Framing

Where described as framed, all joinery shall be put together with well fitting mortise and tenon joints and glued and wedged up solid. Final wedging up shall not be completed until fixing of joinery is commenced. All glued joints shall be cross-tongued and all hardwood joinery shall be secretly fixed. All joinery to be painted shall be knotted and primed with an approved primer before leaving the shop but not until inspected by the Engineer.

1.2.39 Fixing of Frames

Where windows or door frames are built into existing openings, the jambs shall be plugged at the door head and sill and, in the case of door frames or windows over 900 mm high, at one intermediate point per side. (This timber may be fixed with nails unless otherwise described). Timber Components

1.2.40 Flush Doors

Generally flush doors shall have a minimum thickness of 40 mm. They shall be faced both sides with hardwood veneered faces. Flush doors shall be approved by the Engineer and shall comply with DIN 18101 and DIN 68706. All edges shall be bevelled and lipped with hardwood tongued into the edge of the door. The core of solid core flush doors shall be constructed of longitudinal laminations of precision planed timber, butt jointed and glued with resin based adhesive under hydraulic pressure, the whole forming a rigid fire-resistant raft. All external doors shall be glued with AW1OO grade adhesive and faced with AW1OO bonded exterior grade plywood. Fire-resistant flush doors, if required, shall be constructed in accordance with DIN 4102.

1.2.41 Hardwood Doors

Hardwood doors shall be constructed out of teak or similar approved hardwood, with 100 x 38 mm stiles, 125 x 28 mm top rails and 225 x 38 mm middle and bottom rails. Where required, the doors shall be glazed with 6 mm wire polished plate glass, fixed with hardwood glazing beads and shall provide a fire-resistance in accordance to DIN 4102.

1.2.42 Hardboard In Doors

Doors shall not contain hardboard.

1.2.43 Folding Shutter Doors

Folding shutter doors shall be proprietary sliding shutter vertically folding doors with panels constructed from galvanized steel and jointed together by galvanized steel hinge sections. The doors shall be approved by the Engineer and shall be supplied complete with all necessary tracks, posts, soffit and jamb closing pieces, etc.

1.2.44 Frames

In general, frames, architraves and extension pieces shall be manufactured from red and/or whitewood timber and shall include the use of finger-jointed material. If exposed in the laboratory the frames shall be in hardwood.

1.2.45 Floor Runners

Floor runners shall be constructed from 5 x 10 cm and 5 x 7 cm hardwood joists. The joist hangers shall be of the same type of wood and size.

1.2.46 Timber Ceilings

Ceilings under floor and roof structures of other than concrete construction shall be of 10 mm termite proof "Treetex" fixed with galvanized nails to 50 x 80 mm hardwood battens provided at 600 mm centers in both directions and secured thereto by 25 x 5 mm hardwood cover fillets to form squared pattern of approximately 600 x 600 mm; prices for ceilings shall include for battens, cover fillets, any cornices indicated at junctions of ceilings and walls, and for three coats of oil distemper. 7.2.47 Timber Boarded Floors Flooring shall be executed in accordance with DIN 18356 and shall not be laid until all wall and ceiling coverings have been formed or constructed. Timber boarded flooring shall be of 30 x 100 mm apart measured in any direction. Boarded flooring shall be secret nailed to hardwood battens laid at a maximum of 500 mm centres and - if on a concrete or reinforced concrete floor slab - spaces between battens shall be filled with screed. Heading joints shall be formed over battens and shall generally be splayed unless specified to be tongued and grooved. Floor boards shall be thoroughly cleaned off and polished on completion. Prices shall include for the provision, fixing, and laying of battens and screed.

1.2.47 Timber Soffits

Fascia boards and barge-boards (to gables) shall be constructed of selected 25 mm planed selected hardwood as indicated to heights shown, and, where closed soffits are indicated, such soffits shall also be constructed of hardwood 20 mm thick, well planed, tongued and grooved, "V" joined, and fixed to 50 x 50 mm battens. Soffits shall receive three coats of approved oil paint.

1.3 Glass and Glazing

1.3.1 General

The Contractor shall supply all the glass required in those items of plant, furnishings and fitments in-cluded in the Contract. Glass shall be to DIN 1249, or equivalent, and free from all defects. Sheets shall be SQG (selected quality glazing) and of approved weight. Labels showing glass manufacturer's name, type of glass thickness and quality will be required on each piece of glass. Labels must remain on glass until it has been set and inspected. All glazing compounds shall be delivered in labelled containers with the seals unbroken.

1.3.2 Materials

Obscured glass shall be rough cast to an approved pattern, untinted and 6 mm nominal thickness. Wired glass shall be transparent with a polished surface, 6 mm thick, selected and cut parallel to the reinforcement. Where individual panels are adjacent the glass wires shall line up. Clear float glass shall be 6 mm thick. Putty for glazing to timber frames shall be in accor¬dance to DIN 18540, and to metal frames shall be of approved manufacture.

1.3.3 Size Delivery And Storage

The Contractor shall determine the actual sizes required by measuring frames to receive the glass at the work site of from guaranteed dimensions provided by frame supplier. Dimensions for glass and frame shall provide minimum clearance equal to glass thickness for single glass on all four sides. The sealed space between face of glass and fixed or applied glazing stops shall be not less than 3 mm minimum. The Contractor shall deliver glass to site in suitable containers that will protect glass from the weather and from breakage.

1.3.4 Installation

Clear glass shall be used except where indicated otherwise. The glass shall be cut and installed with any visible lines or waves running horizontally. Glazing in wood shall have rebates and beads primed and painted. The glass shall be firmly seated into the previously beaded and back-bedded rebate with glazing compound and secured in place with wood beads, attached with not less than 2.5 cm length finish nails, or flat headed screws, countersunk and set approximately at 15 cm centres. Nails or screws used in beads shall be of the corrosion resistant type.

1.3.5 Tests

Glazing shall be flooded from top to bottom using water from a hose without nozzle. Any leaks revealed by the hose test shall be corrected as directed.

1.3.6 Cleaning Up

All glass shall be cleaned at the completion of construction and any broken glass replaced. The glazing shall be maintained in a clean condition until the date of handing over the works.