C11: Joinery elements

11.1 WINDOWS

Timber main frames and casements to be Douglas fir complying with Class J10 of EN942, all in accordance with architect's drawings and details. Timber glazing beads to comply with Class J2 of EN 942 and be fixed with stainless steel pins. Lamination of sections is permitted. Finger jointing of individual laminates is permitted, but not of whole sections nor on exposed surfaces intended for a natural or satin finish. Inserts and fillers are not permitted. There shall be no signs of insect attack. Moisture content of timber at time of installation is to be 16±3%. Resin adhesives shall comply with grade D4 of EN 204. Workmanship shall be in accordance with BS 1186: Part 2. Safety in accordance with BS 5588: Part 1. Preservation to minimum of Hazard Class 3A in accordance with BS 8417 (table 6 for organic solvent, table 8 for boron and table 9 for waterbased).

Glazing and full beading

Double-glazed units as noted on architect's drawings shall be hermetically sealed employing the `Double Seal System' and in accordance with BS 5713.

The unit must be full bedded with an approved mastic compound. The compound manufacturer's instructions must be followed. With timber frames, faces in contact with the compound must be completely sealed with an appropriate sealer to prevent oil absorption from the compound. Some preservation treatments used for timber frames can adversely affect compounds. However, two coats of recommended sealer on the relevant frame surfaces are a suitable precaution with most treatments. Nevertheless, exceptions exist, e.g. wax or silicone-based water repellents and water-based acrylic primers. The space between the edge of the unit and the rebate must be completely filled with compound before fitting the beads. The beads must be well bedded with compound to both frame and unit. Exposed edges of compound both inside and outside must be chamfered, so as to shed water. After bedding the glazing with mastic until it is exposed for chamfering allow for a second external face sealing with approved mastic using a narrow finishing nozzle to ensure a complete waterproof window. No linseed oil putty may be used. The unit must be secured in the frame by sprigs or spring clips.

Edge clearance, which must not be less than 3mm, must be maintained by distance pieces of non-absorbent non-compressible material. They should be placed opposite each other on each side of the unit, not more than 300mm apart, opposite the securing points of the beads but not immediately above setting or location blocks. They should be approximately 40mm long, 3mm thick and a breadth of 3mm less than the rebate depth.

Distance pieces are not necessary with mastic strip designated as load bearing by the manufacturer.

Approved mastic

The following, approved mastic may be used: (state brand name) with primer as required, or equal and approved by the architect.

Setting blocks

Minimum length 30mm/sq. m of glass; plasticised P.V.C (to BS 2571 softness No. 35-45) or neoprene to Shore hardness No. 80-90.

Location blocks (to casements or the like)

Minimum length 25mm; plastics P.V.C. (to BS 2571 - softness No. 35-45) or neoprene to Shore hardness No. 80-90.

Distance pieces

Minimum length 25mm; plastics P.V.C. (to BS 2571 - softness No. 35-45) or neoprene to Shore hardness No. 80-90.


11.2 DOORS, DOORSETS AND FIRE-RESISTANT SCREENS

External doors

European or American white oak door, TG&V panels fixed to framing with stainless steel or silicon bronze nails. Stiles and rails shall be jointed with stub-tenons or non-corrosive mechanical devices. The framework shall be square when assembled in a true plane, and the parts shall match each other in thickness. Minimum door thickness 50mm, all in accordance with architect's detailed drawings. Preservative treatment shall be provided to minimum Hazard Class 3A. The door locking mechanism shall be three point to eliminate warp and provide additional security. Moisture content 16±3%. A full size prototype to be made up by the joinery works for approval by the architect prior to fabrication of all the doors. Glazed external doors shall have a minimum frame thickness of 55mm.

Interior doors

Interior panel doors made of Scots pine to Class J10 of EN942. Glazing beads, where required, shall match and shall be supplied loose. Door frames and linings to match and suit finish and thickness of door. Minimum thickness 45mm. Moisture content 12±2% at time of manufacture and site installation. Workmanship shall be in accordance with BS 1186 Part 2.

Flush solid door

A solid core door shall consist of a suitable 100% core of solid timber covered on both sides with facings of minimum 6mm plywood or other architect-approved material; with or without apertures for glazing or ventilation louvres. Quarter-sawn white oak veneer to be used throughout or as detailed on architect's drawings.

Fire-rated doors

Flush solid core doors, certified half hour fire resistance to comply with BS 476, including intumescent strips and smoke seals as necessary; quarter-sawn white oak veneer both sides, all in accordance with architect's drawing and Fire Certificate requirements. Joinery manufacturer shall produce a relevant Fire Test Certificate acceptable to the fire officer, and in accordance with the Fire Certificate requirements.

Fire-resistant screens

Fixed glazed fire-resistant screens shall be installed in accordance with the man-ufacturer's instructions and recommendations and as detailed on architect's drawings and Fire Certificate requirements.

Fire resistant glass

Supply and fit (state brand name) or equal and approved by the architect multi-laminated glass assembled with clear intumescent interlayers in accordance with the manufacturer's written instruction to meet the integrity and insulation criteria, according to BS 476: Part 22 and the safety requirements of BS 6206. Note the fire-resistant glass cannot be cut on site and the edge protection tape must not be removed or damaged.
In addition the following glazing instructions must be adhered to.

* Do not allow any contact of the glazing's edges with water.
* Do not install fire-resistant glass in locations where the glass temperature might exceed 40°C.
* Always refer to the fire test reports.
* Avoid all glass to metal contact.
* Do not exercise any restraint on the glazing.
* Do not damage the glazing's edges or the protection tape.
* Keep the rebates dry and free from aggressive products (acids, organic solvents, etc.).
* Use hardwood setting blocks or equivalent (Shore hardness A75).
* Provide an edge clearance of 4-5mm.
* Provide front and back clearances of 4-5mm, using closed cells foam tape.
* Provide a rebate depth of minimum 20mm.
* Apply a neutral silicon sealant immediately after sealing.


11.3 STAIRCASES

Softwood staircases

Strings shall be Scots pine to Class J30 of EN 942 where not exposed. Handrails, balustrades, newels, treads and risers shall be Class J30 of EN 942 where painted or Class J10 when exposed and decorated with a clear polyurethane finish. Sizes and tolerances shall comply with BS 585: Part 1 for domestic use only. Workmanship shall be in accordance with BS 1186: Part 2. Adhesive shall be one-part polyvinyl acetate complying with BS 4071. The moisture content at the time of manufacture and installation shall be 12±2% and all in accordance with the archi-tect's detailed drawings.

Hardwood staircases

The hardwood staircases shall be constructed from prime quality white oak with approved joints and adhesives all in accordance with architect's detailed drawings, including slip resistant inserts to tread nosing and two-pack matt polyurethane finish. Moisture content at the time of manufacture and installation shall be 12±2%.

Building regulations

Landings, balusters, handrails, and step rise and going shall comply with the current technical Guidance Document to the Building Regulations for their respective end use.