FOI Request - Double Glazing Inspections
Request 101003428297
1. Please tell if building control in your townhall carry out double glazing inspections to residential properties that are replacing windows
2. Please say what double glazing standards are used by you with regards to for example, installation methods, window positioning, bolting, washers, rain ingress prevention, shape, size, measurement, extrusion and glass quality, beading, silicon, foaming, sill, stays, locks, accessories, spacers / shims, tools etc
Response 30-11-2023
1. Replacement of windows does not require building warrant approval and therefore no inspections by building standards are carried out.
2. We are currently reviewing our specification of windows but our current specification is below:
WINDOW SPECIFICATION
8. The type of window required will be a “ Fully Reversible, Peder Nielsen PN Uni Hotel Hinge type”, Compass Windows, 13 Hass Road, Dungiven, N.Ireland BT47 4QH, or equal & approved. All being able to be cleaned from inside the building accordance with Building Standard 4.8.3. In specific cases such as listed buildings, conservation areas, noisy areas, opening sizes, specific Client requirements including the window type may vary, where a separate specification document will be made available.
9. Generally astragals will not be required.
10. The windows are to be supplied as complete factory finished, primed, undercoated and two top-coat coated, glazed products ready for installation in accordance with the manufacturer’s printed instructions.
11. The windows are to: -
• Meet the minimum standards set out in BS 644, the main British Standard for wood windows, or equivalent standards from other countries.
• Meet the performance standards for wind and weather resistance of BS 6375 Part 1, (or equivalent standards from other countries), with the following performance requirements;
i) Air Permeability = 600pa (Class 4)
ii) Water Tightness = 900pa (Class 9A)
iii) Strength & Sustainability = 2400pa (class AE2400)
• Meet the minimum performance standards for operational aspects of BS 6375 Part 2, (or equivalent standards from other countries).
• Be accredited by an independent UK body to prove compliance with these standards and evidence of compliance to be submitted with tender.
• Be manufactured from timber, sourced legally from sustainably managed forests.
• Have the required service life warranties for durability, paint life, ironmongery and insulated glass units.
12. The windows frames are to be manufactured from treated high quality redwoods sourced from sustainable managed forests with a minimum of 70% FSC materials. Engineered timber with straight, knot free sections are acceptable, where joints are not visible through final top coat and where there are no finger joints within 300mm or each other, or within 300mm of a frame intersection (i.e. a corner join). Approved window manufacturers shall be FSC/PEFC certified with 3rd party Chain of Custody Certification.
13. All timber including frames, beads, cills etc are to be in accordance with BS:EN 942:2007 appearance class J2 to J10.
14. Moisture content on delivery 13% - 19%
15. Window frames are to be treated with a pressure treated or flowcoated preservative to allow the required guaranteed service life. The treatment is not to affect the end-of life disposal of the windows.
16. The detailing of the window should ensure that at least a 4 degree slope is achieved on horizontal sections such as cills, bottom beads and transoms to allow for rainwater run-off and sharp edges should be avoided to allow for good paint adhesion. Large cill extensions and overhangs are to be avoided.
17. The window frames are to have factory applied brilliant white opaque water based heavily pigmented opaque coating / finish both inside and out to achieve a high sheen gloss finish.
18. All gaskets shall be Aquamac/QLON (or equal and approved) with a minimum service life / warranty period to match the required 35 year service life of the window frame. Any equivalent gaskets must be impervious to paint and stain during the re- decoration process. Woolpile gaskets will not be acceptable for this purpose.
19. All frames sections to be fitted with continuous double gaskets to all 4 sides of the frame, providing extra Air and Water protection for exposed sites
20. Ironmongery is to have a powder coated White or Brushed chrome finish.
21. Generally glass is to be to BS 952 and the relevant parts of BS EN 572 and be free of scratches etc. and any other defects. Generally glazing is to be to BS 6262.
22. The window is to be factory glazed with 24mm thick sealed double glazing units with warm edge spacer bars. Composition of glass is to be (From Outside): 4mm Float – 16mm argon filled cavity – 4mm float glass with super low E Coating. If external beading is used then security clips are to be fitted in addition to security beads. Alternatively glazing with a closed cell double sided security tape will also be acceptable.
23. Bathroom and toilet windows are to have obscure Cotswold pattern glass.
24. All existing TV / communication cables to be sleeved and taken around the side of window frame.
25. Provision must be made to have a slot cut into existing masonry cill to accommodate a 15mm sleeve to protect cables future TV/Communication cables.
SUSTAINABILITY
26. The windows are to be manufactured from timber that is independently certified as legal and sustainable by a scheme recognised by CPET i.e. FSC, PEFC, SFI or CSA and be accompanied by 3rd party traceable chain-of-custody certification
27. The windows should be rated A+ according to BRE Green Guide stipulations.
28. The windows should be A rated in accordance with the BRE’s Climate Change indicators.
ENERGY-EFFICIENCY
29. Windows are to meet or better the Building Standard requirements for energy efficiency.
30. The overall U-value of each window (Based on a 1200x1200mm finished sixed frame) is to be a maximum of 1.2 W/m2K and warm edge technology (or certificated equivalent) is mandatory on all windows with supporting documentation
31. Building Standard’s Accredited Construction Details (Scotland) are to be adopted i.e. each window installation is to be twice sealed, once externally and once internally behind cills, ingoe cover plates and soffit linings else kept tidy and unobtrusive.
VENTILATION
32. Ventilators to be fitted as standard to head of frame to meet statutory requirements.
33. All windows are to have at least one opening casement / sash and ventilation for all rooms is to comply with Building Standard 3.14.3 Ventilation.
34. Trickle ventilators are to be integral to frame with no external hoods.
35. Internal trickle vent covers should be of steel/aluminum construction and should be made with an easy to operate slide or flick function, able to snap open/closed, and with a White finish such as Titon Trimvent 90 or equal and approved.
36. When in the closed position, the trickle ventilators must permit no greater airflow than 0.98 m3/hr at 100ps (With independent test verification)
37. The Egress slot, between sash and frame, should be fitted with a “bug guard” or perforated mesh guard to prevent insect access.
IRONMONGERY
38. All Ironmongery to meet ‘Secure by Design’ Standards and be tested in a UKAS testing house to meet the requirements of BS7950.
39. Ironmongery to be supplied in brushed chrome finishing’s with a minimum of a 10 year warranty
40. Handles are to be “press to release” via a button with auto latch closure. They should be BBA approved and manufactured to BS EN 12744 and electroplated in accordance with BS EN 12540.
41. Hardware should be tested BS3745 / ISO Standard 1462 for corrosion resistance and manufactured to certified quality system DS/EN 9001: 1994, and should be hidden and not exposed to the elements.
42. All Ironmongery should be salt spray tested to a minimum of 120 hours.
SAFETY AND SECURITY
43. Only ground floor windows are to be Key lockable and all windows are to have travel restrictors. Windows situated first floor and above should be “press to open” hardware or equivalent..A PN locking block to be fitted to each window to prevent misuse.
44. The supplied windows are to be licensed under the Secure by Design scheme and are to comply with BS: 7950: 1997.
45. An ‘escape’ window is to be provided in every basement apartment and in every apartment in an upper storey at a height not more than 4500. (An escape window is a window that complies with Building Standard 2.9.4.)
46. The requirements of Building Standard 4.8.2 “Collision with Glazing” (where window sill height is less than 800mm from floor level) will be satisfied by using toughened safety glass in both inner and outer pane of double glazing units, in accordance with BS 6262: 2005 Part 4. The Contractor should make full allowance for this in his tender rate.
47. All windows should be capable of being cleaned in accordance with Building Standard 4.8.3 “Cleaning of windows and roof lights” and 4.8.4 “Guarding for windows for cleaning”.
48. The control device i.e. handles, restrictors etc should comply with Building Standard 4.8.4 “Access to manual controls”.
49. The Contractor is to provide the Tenant with 1 key per Window, and keep 1 key per house for the Client at the end of the contract.
INSTALLATION
57. Tenants are to be given sufficient advance notice of when work will be carried out to their home so that they may remove curtains, ornaments, pictures, electronic equipment valuables etc in advance. As the houses are occupied every care is to be taken of the contents. Dustsheets are to be used for entire rooms.
58. Each window should be replaced in one operation and no opening is to be left overnight without either the old or new window fixed in position. If during the day there is to be a delay between the renewal and the fitting of the new window, then a temporary screen should be fitted.
59. Installation is to be carried out to the manufactures printed instructions by “time served” joiners and if the manufacture requires it fitters are to be certified by him as competent installers.
60. Pre-installation storage is to conform to manufacturer’s printed requirements
61. Stainless steel fixings and ties are to be used.
62. Cover by the existing jamb / soffit check over the frame is to be minimum 12mm at the head & 12.5mm at the jamb in addition to any tolerance space. No sub-frame or cover-plates to be visible from the external aspect.
63. Sub-frames are to be installed to all window edges to ensure a tight fit to internal wall ingoes. Sub-frames are to be treated and continuous from top to bottom of each side of the opening and along the soffit as necessary.
64. External and internal finishes are to be as required for a complete and tidy installation. In both cases the Contractor is to include for any alteration or damage to the existing to be made good including decoration.
65. External and internal mastic seals are to comprise a polyethylene backing / isolating rope or tape sealed with Arbosil 1096 one part low modulus silicone sealant (or equal and approved), applied to prepared joints all in accordance with the manufacturer’s printed instructions including the use of all primers etc.
66. The Contractor is to fit new architraves, curtain plates, cills, aprons, soffits and ingoe linings in pre-finished, MDF/ boarding to suit, with all corner joints mitered.
Architraves are to match door architraves in style, size and the cill projection is to match the existing. Where ingoes and soffits are plastered on the hard, these are to be covered over in pre-finished (white gloss painted), MDF boarding to suit.
67. The Contractor is to fix the Tenant’s curtain rails to the new curtain plates.
68. The window supplier, or his agent, is to make post installation inspections of all installations to ensure all windows are installed to their satisfaction. They are to advise of any corrective actions required and the remedial work is to be completed ahead of the issue of the Certificate of Practical Completion.