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Ventrolla craftsmen take both the art and science of sash window renovation to a remarkable level.
Ventrolla products and procedures for binder conservation have extended the scope of long lasting wood repairs far beyond traditionally practised methods.
VR90, the Ventrolla two part epoxy resin system, is effective even in areas thought to be beyond redemption.
Ventrolla craftsmen apply VR90 to reinforce tenon joints and perform small to medium sized repairs. It works by penetrating the existing wood to form an extremely strong bond, and is then profiled and primed ready for painting.
With larger repairs, all defective timber is removed and new timber spliced in, using VR90 to form a permanent joint.
From over 100,000 sash windows inspected by Ventrolla every year, only 5% of wood actually needs to be replaced.
It is extremely rare to find a window that is beyond the scope of the Ventrolla repair service. In such a case, individual windows can be re-built to replicate the original design.
Repairs to sash tenon joint
Cill and bottom rail replacement. Tenon repairs were carried out with VR90.
A well designed and maintained sash window typically needs a 3mm gap around the sashes to enable the window to open and close easily. Over the years, continual use and painting result in substantial changes to the operating tolerances.
Ventrolla's aim is to restore each sash window to its original performance standards and upgrade in line with the comfort levels expected of a modern window.
At the heart of this achievement is the Ventrolla Perimeter Sealing System. Winner of the Design Council Award for 'outstanding British innovation', this patented system is unobtrusively installed without compromising the original appearance of the window.
Patent numbers: 21 400 64B UK..55129 Ireland.
See Technical Data Sheet I
In our experience Weatherfin is the ultimate high performance weatherseal for sliding sash windows. It achieves the dual requirement of high performance sealing and low friction sliding.
Ventrolla installs Weatherfin in a range of thicknesses from 3mm-15mm. The polypropylene fibres are independent of each other, which ensures an efficient seal even against irregular surfaces.
BS 6375 Part I (1989) is used for comparing the performance of replacement windows. Independent testing by a NAMAS approved laboratory has shown that the Ventrolla Perimeter Sealing System can meet the highest requirements of this British Standard, achieving even better than Class C.
With the installation of the Perimeter Sealing System, air changes per hour are substantially reduced, to the building's adventitious ventilation rate (typically 0.7ach). The potential for energy saving is approximately 85% of that offered by a double glazed unit.
Minimising the air gap around the sash window frames by installation of the Perimeter Sealing System can lower sound penetration by up to 10dB, which is equivalent to reducing noise ingress by 50%.
SPECIFICATION
VERTICAL SLIDING SASH WINDOWS
FULL Ventrolla System - both sashes slide.
The sashes are carefully released and removed. Each sash is planed and adjusted to best fit. Where fitted, sash cords are renewed, balance weights added as necessary and the pulleys serviced. Where the sashes are counter-balanced using springs, these are serviced/re-tensioned as necessary. (Unless included on the Inspection Sheets if pulleys, weights, springs or chains need replacing, these will be extra to contract). Any screw holes, decay or packing under catches will be made good and catches fitted correctly.
Barrel locks fitted through the meeting rails will usually be removed and the holes filled (as these interfere with the weather-stripping and are unlikely to align after overhaul). We recommend that either a lockable brass Croft catch or sash locks be fitted at the meeting rails on Downstairs and vulnerable windows. (The manufacturers recommend one sash lock for windows less than 900 mm wide and two sash locks for windows greater than 900 mm wide.) These have been included where indicated on the Inspection Sheets.
The Ventrolla System is then installed in the meeting rail and the underside of the bottom sash and new Staff Beads with Ventrolla pre-installed are provided around the inside of the frame.
With the Standard Ventrolla System, the Parting Bead (between the two sliding sashes) is replaced by our patented 2 part extruded bead with Ventrolla draught strip installed. A ‘U’ section is screw fixed into the parting bead groove and the Ventrolla parting bead push fits into this.
(The Ventrolla parting bead is not fitted to heads in boxes with curved or bowed heads. For these windows, the top of the upper sash is machined instead and fitted with a single pile carrier and pile).
The Ventrolla system meets the highest requirements of BS6375 Part 1: 1989 in respect of air leakage.
HALF VENTROLLA SYSTEM: Installation is similar to the FULL Ventrolla System, except that the bottom sash only slides and the top sash is sealed.
SASH REMOVAL SYSTEM (Sliding sash windows fitted with sashcords only)
The Staff Beads are fitted using press-studs/screws for easy removal when required for painting or repairs. The sides of the top and bottom sashes are fitted with concealed housings to accept the demountable sashcords fitted.
When the Staff Beads are removed, the bottom sash lifts out and the sashcord can be disengaged.
When re-engaging the sashes, the cord brakes can be pushed up to the pulleys to prevent the weights in the boxes from pulling up the sashcords. This frees both hands for easy re-engagement following maintenance.
To remove the top sash, the Parting Bead is eased out and removed (as for painting) and the top sash then lifts out and is disengaged in the same way.
This simple system allows all maintenance work (including painting) to be carried out from inside without the need for expensive and unsightly scaffolding.
HORIZONTAL SLIDING SASH WINDOWS (YORKSHIRE SLIDERS)
The sliding sash is released and removed. The guide bead under the sliding sash is renewed if necessary and excess paint removed from the frame. The sash is planed and adjusted to correct tolerance and, following repairs, the Ventrolla System is installed as follows:
To facilitate sliding, the underside of the sliding sash is routed on both sides of the guide groove to accept pile carriers. The vertical meeting rail of the sliding sash and the edges of the remaining two sides are also routed for the pile carrier. Pile of appropriate height with projecting weatherfin is then inserted.
Where windows are fitted with internal beads around the frame, these may be replaced with new beads with the pile installed.
TIMBER CASEMENT, HOPPER, PIVOT & FRENCH WINDOWS
The opening sashes are carefully released, removed and planed and adjusted as necessary to fit well. Excess paint is removed and, following repairs, the Ventrolla carrier system is routed into the edges of the openers. Pile of appropriate height and with projecting weatherfin is then inserted into the carrier and the window re-assembled.
In exceptional cases where internal beading is fitted and existing hardware and details permit, new internal beads may be fitted to the sashes or frames with Ventrolla carrier and pile inserted where this is deemed by Ventrolla to be appropriate.
EXTERIOR DOORS
The Door is removed from its hinges and planed on the underside as necessary. Following repairs as indicated on the Inspection Sheets, a 6 mm thick plant-on is fitted around the door frame externally, adjusted to the contour of the door as nearly as possible. The frame is then routed to accept the Ventrolla carrier and a Ventrolla pile of appropriate height and with projecting weatherfin is inserted facing the door. The underside of the door is also routed to accept the carrier and pile.
If there is no existing threshold bar, or if the existing one is worn or unsuitable, a new mahogany threshold bar of size 22 x 29 mm will be fitted bedded on mastic and screwed into the floor under the door.
Any worn hinges, locks and door furniture that cannot be made to function correctly may have to be replaced at extra cost.
As external doors, but with thin hardwood cover strip under door at carpet joint as necessary.
During installation of Ventrolla systems, defects in sashes and frames as indicated on the Inspection Sheets are made good and primed ready for painting by others. Repairs are carried out where appropriate with the Ventrolla VR90 epoxy repair system. VR90 is very strong, rot-proof and will not crack and is, therefore, especially suited to the repair of joints.
Decayed and damaged timber is routed out to expose prime wood which is then sealed and stabilised using VR90 WS Solution. Cavities formed after routing are filled with bulk filler and finished with the VR90 2-part epoxy system and allowed to set. The repairs are then moulded to match the existing profile and sanded. Larger repairs are shuttered as necessary.
Partial or full replacement of timber may be appropriate for some repairs such as linings, outer cheeks and glazing bars. Any timber spliced into existing will be compatible and the joints formed with VR90 where appropriate.
Replacement joinery will be supplied in the same style as original, where known and appropriate, in similar sized sections with similar mouldings.
Replacement joinery in softwood is treated with Organic Solvent Preservative applied (where practical) by double vacuum method in accordance with BS5589 and primed for painting by others.
Where existing cills are beyond economic repair, the entire old cills will be carefully removed and new hardwood cills fitted. As a part of the cill replacement, partial replacement of the pulley stiles and external cheeks will be carried out.
Unless otherwise stated, cracked panes of glass as indicated on the Inspection Sheets will be replaced with clear 4 mm float glass, and cracked and loose putty replaced as indicated.
Unless specifically stated, we have not included for any cleaning of glass or rubbing down of sashes prior to decoration.
Cast brass sashlifts, catches, sashlocks, etc will be fitted as indicated on the Inspection Sheets.
Painting (other than priming of repairs) is NOT included.
Good painters experienced in painting sliding sash windows should find painting them easier with the Sash Removal System, although a little preparation is needed to protect the pile and carrier.
It is the responsibility of the customer to ensure their painter is made aware of the System and shown a copy of the Painting Instructions issued by Ventrolla. We strongly recommend that you ask your
painter to attend a demonstration of the System whilst we are on site and instruct him how to remove the sashes during painting.
Any burning off or chemical removal of paint should be completed before the installation.
Existing secondary glazing to be taken down and stored on site/disposed to tip. Reveals and architrave or plaster up to 50 mm around frames to be carefully removed and existing windows taken out. Opening to be cleaned and prepared by others and new windows secured in place and sealed all around externally with stone/brick coloured mastic. Reveals and architrave or plaster to be reinstated internally.
New traditional sliding sash windows to be constructed from double vacuum treated pine with hardwood cills. Sashes to have authentic moldings on the internal faces. Upper sash(es) to be fitted with vertical glazing bars and horizontal glazing bars. Lower sash(es) to be fitted with vertical glazing bars and horizontal glazing bars./Sashes to be fitted with glazing bars as indicated on the drawings/schedule.
All sashes to be single/double glazed and counterbalanced with cords and weights over brass pulleys. Bottom sashes to be fitted with a pair of cast brass sashlifts and croft catch and one/two sash locks in brass/white finish.
New windows to be supplied with the Full Ventrolla System including the Sash Removal System for easy maintenance.
Windows are supplied with one coat of acrylic primer ready to accept undercoat and gloss by others.
Please note that where new putty pointing has been required in the repair of the windows there may be residue putty adheres to the glass. Ventrolla recommend that you do not clean this away until the windows have been fully painted and weather proofed. This is recommended in order to protect the integrity of the replacement putty pointing.
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