TECHNICAL

TECHNICAL

Our window restoration work is often undertaken as part of a building renovation project, where the owner or developer will seek to upgrade the building to meet modern standards, perhaps incorporating a change of use.

This page gives details of the Building Regulations which apply to window refurbishment; plus information about testing standards and performance.

Building Regulations

The following Approved Documents to the Building Regulations (England & Wales) are relevant to window restoration.

Approved Document E – Resistance to the passage of sound. Window restoration can improve the acoustic performance of windows in two ways:

  • By draught proofing, which also offers acoustic benefits. Our draught proofing system can improve the acoustic performance of a window by 6-10 dB (A).
  • By upgrading the glazing to modern double-glazed sealed units. The glazing units we install offer a typical sound reduction of 31 dB Rw (27 dB Rw where traffic is heavy).

Note that the optimum performance of the window assembly is achieved through a combination of perimeter sealing and double glazing. The assumption is a 3mm perimeter gap.

Approved Document L – Conservation of fuel and power. As for acoustic containment, the answer to heat loss through windows and doors is by draught proofing and double glazing.

  • Research has shown that draught proofing can reduce air leakage in windows by as much as 50%, significantly reducing the energy needed to heat the room.
  • The slim glazing units we install have a tested U value of 1.9 W/m²K. Lower figures are available for units with larger cavities and thicker glass. Test certificates for the centre U value of the glass are available on request.

Approved Document K – Protection from falling, collision and impact. This includes content from the now-obsolete Approved Document N “Glazing - Safety in relation to impact, opening and cleaning”. We provide window furniture which can limit the opening of sash windows, to allow ventilation but also reduce the risk of falling.

Approved Document Q – Security – Dwellings. Our window refurbishment work can aid security through increasing the strength of glazing, by installing double glazed units. We also provide window furniture which inhibits sash window opening, and lockable fasteners.

Standards and testing

The perimeter sealing system we use has been tested for performance in accordance with the following standards:

• Air permeability – Test method: BS EN 1026:2000. Classification: BS EN 12207:2000. Result: 600Pa (Class 3)

• Water tightness – Test method: BS EN 1027:2000. Classification: BS EN 12208:2000. Result: 300Pa (Class 7A)

• Resistance to wind load test pressure, and frame deflection – Test method: BS EN 12211:2000. Classification: BS EN 12210:2000. Result: 2400Pa (Class AE2400)

• Weather tightness (exposure category) - Test method and classification: BS 6375 Part 1:2009 Result: 2400

The results given are for a box sash window with our sealing system installed, tested under laboratory conditions. They are indicative of what may be achieved on site for a restored window of a similar construction. Performance may vary according to window type. A copy of the test certificate from BM TRADA (a UKAS-approved testing station) is available to download.

Caring for restored windows

On completion of every project we issue an O&M (Operation and Maintenance) manual specific to the site, which gives details of how the windows should be maintained.

We also appoint a member of our team to provide after-sales support on each project.

Some general guidance:

• It is good practice to inspect windows regularly for any early signs of movement or cracks.

• Re-painting should be undertaken every 4-5 years, or 6-7 years if a resin repair has been carried out.

• Polished Brass ironmongery should be cleaned regularly with warm soapy water, plus an occasional application of a good wax polish. Chrome ironmongery should be cleaned with warm soapy water, plus chrome polish if desired.

• Weather seals benefit from an occasional wipe with a damp cloth, to remove dust and debris and refresh the pile.

Training seminars

We are able to organise training seminars / CPD presentations for specifiers with our partner Repair Care. One of their technical experts covers issues such as timber window refurbishment, preservation and conservation.

Please contact our team to discuss your training requirements and book a seminar.

Our experienced team will be more than happy to answer any technical questions about our window restoration work. Contact us today.

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