Loading document...
Mc² Project Reference No. P.2600
Ramsey and District Cottage Hospital Cumberland Road Ramsey Isle of Man
Prepared for:
Department of Health and Social Care 1st Floor Belgravia House Circular Road Douglas IM1 1A
28 CHURCH ROAD
PORT ERIN ISLE OF MAN
IM9 6AQ
Tel: 01624 624738 E-mail: [email protected]
The Client, Department of Health and Social Care, intend to carry out works at Ramsey and District Cottage Hospital and set out herein are details of the remedial works to be carried out to address the defects in the roofs. This statement should be read in conjunction with Drawing No P.2600/PA/02 - Diagrammatic Part Plan of Roof
Carefully remove the lead apron and stepped flashings on the chimney stack and roof ridge and dispose of off-site.
Carefully strip twelve rows of slates x 1.5m wide together with timber battens and underfelt below the peak, both sides of the ridge. Sound slates to be cleaned of moss and algae and set aside for reuse. Defective slates disposed of off-site.
Cut out and remove damaged or decayed timbers around the reduced chimney stack and replace with treated timbers of an equivalent size.
Extend the ridge board to the verge with treated timber member of equivalent size complete with a robust scarf joint.
Infill the roof void with treated timber rafters of equivalent size and stitch to the new ridge board and sides of the existing rafters with corrosion-resistant screw fixings of a suitable size and gauge.
Cover the new rafters with Tyvek roofing membrane lapped 150mm min to the existing underfelt all around.
Slate over the roof void reusing existing sound slates supplemented with first quality matching salvaged slates secured with alloy clout nails min one per slate. Every slate to be clipped at the verge. Secure existing adjacent loose slates with black coated stainless steel slate hooks where required.
Supply and fit Code 7 matching lead ridge capping in 1.2m lengths with covered slip joints allowing for thermal movement and 100mm lap over slates. Use clips/straps at 400mm centres not fasteners. Treat the lead with patination oil immediately after fitting.
Ensure slates are securely fixed and sealed at the verge. Repair/replace verge board where required and prepare and decorate with aluminium primer/undercoat and two coats of gloss paint in white.
Carefully remove two sections of the existing rainwater guttering to the conical roof and set aside for reuse.
Carefully remove the lead cover flashing to the top of the chimney stack and stepped lead flashings at the stack/roof abutments at rear and on both sides and dispose of offsite.
Carefully strip the existing slates around the stack to facilitate its removal, together with timber battens and underfelt. Sound slates to be cleaned of moss and algae and set aside for reuse. Defective slates disposed of off-site.
Cut out and remove any damaged or decayed roof timbers around the reduced chimney stack.
Infill the roof void with treated timber rafters of equivalent size and stitch to the existing rafters and other supporting roof timbers with corrosion-resistant screw fixings of a suitable size and gauge.
Cover the new rafters with Tyvek roofing membrane lapped 150mm min to the existing underfelt all around.
Slate over the roof void reusing existing sound slates supplemented with first quality matching salvaged slates secured with alloy clout nails min one per slate.
Secure existing adjacent loose slates with black coated stainless steel slate hooks where required.
Supply and fit new Code 4 lead concealed soakers at the hip to the conical roof and at the junction with the pitched roof behind. Use clips/straps at 300-400mm centres not fasteners. Treat the lead with patination oil immediately after fitting.
Repair/replace damaged section of fascia board where required and prepare and decorate with aluminium primer/undercoat and two coats of gloss paint in white. Refit the rainwater guttering.
Carefully remove the apron and stepped lead flashings on the chimney stack, sections of the lead roof ridge and clay ridge tiles both sides of the stack. Retain sound ridge tiles and dispose of lead ridge off-site. Carefully remove two clay chimney pots and TV aerial and dispose of off-site.
Carefully strip the existing slates around the stack to facilitate its removal, together with timber battens and underfelt. Sound slates to be cleaned of moss and algae and set aside for reuse. Defective slates disposed of off-site.
Cut out and remove any damaged or decayed roof timbers around the reduced chimney stack. Fit a new section of treated timber ridge board of equivalent size complete with a robust scarf joints both ends.
Infill the roof void with treated timber rafters of equivalent size and stitch to the new ridge board and existing rafters and other supporting roof timbers with corrosionresistant screw fixings of a suitable size and gauge.
Cover the new rafters with Tyvek roofing membrane dressed over the ridge and lapped 150mm min to the existing underfelt all around.
Slate over the roof void reusing existing sound slates supplemented with first quality matching salvaged slates secured with alloy clout nails min one per slate.
Secure existing adjacent loose slates with black coated stainless steel slate hooks where required.
Supply and fit new Code 7 matching lead ridge capping with covered slip joint over the existing allowing for thermal movement and 100mm lap over slates. Dress the new lead ridge under the existing clay ridge tiles min 150mm and secure with clips/straps at 300-400mm centres not fasteners. Treat the lead with patination oil immediately.
On completion, remove any debris arising in the roof void together with the protection plywood sheeting.
Remove the lead cover flashing to the top of the chimney stack, back gutter flashing at the rear and stepped lead flashings on both sides and dispose of off-site.
Carefully strip the existing slates around the stack to facilitate its removal, together with timber battens and underfelt. Sound slates to be cleaned of moss and algae and set aside for reuse. Defective slates disposed of off-site.
Cut out and remove any damaged or decayed roof timbers around the reduced chimney stack.
Infill the roof void with treated timber rafters of equivalent size and stitch to the existing rafters and other supporting roof timbers with corrosion-resistant screw fixings of a suitable size and gauge.
Cover the new rafters with Tyvek roofing membrane lapped 150mm min to the existing underfelt all around.
Slate over the roof void reusing existing sound slates supplemented with first quality matching salvaged slates secured with alloy clout nails min one per slate.
Secure existing adjacent loose slates with black coated stainless steel slate hooks where required.
At the disturbed hip to the conical roof supply and fit new Code 4 lead concealed soakers.
At the pitched roof intersections, remove the lead lining to the upper section of the valley and supporting lay boards and dispose of off-site.
Carefully remove three rows of slates to the upper roof both sides to expose the junction; extend the valley at the roof intersections.
Fit new 18mm structural plywood lay boards between the rafters supported on treated timber battens. Fit 25mm tilting fillets each side of the valley to form 125mm min. wide trough.
Install a continuous strip of Tyvek roof membrane over the valley and tilting fillets and lap to the existing roofing underfelt min 150mm.
Line the valleys with Code 5 lead dressed over the tilting fillets with a welt formed on both ends. Lead to be in 1.5m max lengths and to overlap 150mm min.
Provide new lead soakers and cover flashings to the lower abutment at the pitched roof intersections. Return the lead flashings 90° under the new lead lined valleys to form a weathertight seal to prevent wind driven rain penetrating the roof void at this vulnerable junction. Treat all lead flashings and detailing with patination oil immediately on fitting.
Reinstate the slates either side of the valleys and at the lower abutments to the roof intersections reusing existing sound slates supplemented with first quality matching salvaged slates secured with alloy clout nails minimum one per slate.
Valley slates to be cut on a rake and each row clipped at the valley junction to ensure stability and compliance with BS 5534:2014+A2:2018 Code of Practice for slating and tiling, which requires mechanical fixing of all slates especially at vulnerable points.
On completion, remove any debris arising in the roof void together with the protection plywood sheeting.
Carefully strip the existing slates around five redundant roof cowls to facilitate their removal. Sound slates to be cleaned of moss and algae and set aside for reuse. Defective slates disposed of off-site.
Remove five redundant ventilation cowls together with lead apron and upstand flashings and dispose of off-site.
Cut out and remove any damaged or decayed roof timbers adjacent to the roof voids.
Infill the roof voids with treated timber rafters of equivalent size and stitch to the existing rafters and other supporting roof timbers with corrosion-resistant screw fixings of a suitable size and gauge.
Cover the new rafters with Tyvek roofing membrane lapped 150mm min to the existing underfelt all around.
Slate over the roof voids reusing existing sound slates supplemented with first quality matching salvaged slates secured with alloy clout nails min one per slate.
Secure existing adjacent loose slates with black coated stainless steel slate hooks where required.
The ventilation cowl used as an access for cable and other services entry through the pitch roof to be retained. Carefully unbolt the cover, remove and set aside for reuse.
Supply and fit 316 stainless steel square mesh panel (6x6mmx0.5mmØ) over the concealed aperture and adequately secure ensuring no gaps remain for bird or rodent entry. Refit and bolt the cover to the cowl.
On completion, remove any debris arisings in the roof void together with the protection plywood sheeting.
Carefully remove rainwater gutters, outlets, downpipes and fascia boards on both sides of the roof gable peak and set aside for reuse.
Carefully remove the ridge tile at the apex and three rows of slates either side of the valleys. Sound ridge tile and slates to be cleaned of moss and algae and set aside for reuse. Defective slates disposed of off-site.
Remove the lead lining to the valleys and supporting lay boards and dispose of offsite.
At pitched roof intersections carefully remove three rows of slates to the lower roof both sides to expose the abutment. Remove lead soakers and cover flashing to the abutment.
Fit new 18mm structural plywood lay boards between the rafters supported on treated timber battens. Fit 25mm tilting fillets each side of the valley to form a 225mm wide trough.
Install a continuous strip of Tyvek roof membrane over the valley and tilting fillets and lap to the existing roofing underfelt min 150mm. Dress strip of Tyvek roof membrane over the ridge and down the valleys 600mm both sides.
Line the valleys with Code 5 lead dressed over the tilting fillets with a welt formed on both ends. Lead to be in 1.5m max lengths and to overlap 150mm min.
Provide new lead soakers and cover flashings to the lower abutment at the pitched roof intersections. Return the lead flashings 90° under the new lead lined valleys to form a weathertight seal to prevent wind driven rain penetrating the roof void at this vulnerable junction. Treat all lead flashings and detailing with patination oil immediately on fitting.
Reinstate slates either side of the valleys and at the lower abutments to the roof intersections reusing existing sound slates supplemented with first quality matching salvaged slates secured with alloy clout nails minimum one per slate.
Valley slates to be cut on a rake and each row clipped at the valley junction to ensure stability and compliance with BS 5534:2014+A2:2018 Code of Practice for slating and tiling, which requires mechanical fixing of all slates especially at vulnerable points.
Refit the fascias and rainwater goods, ensuring the joints are sealed watertight. On completion, remove all debris accumulated in the roof void.
Remove a section of rainwater guttering and set aside for reuse. Carefully strip 1.5m² of roof tiles above the water stained ceiling in the Library. Sound tiles to be cleaned of moss and algae and set aside for reuse. Cracked or damaged tiles to be disposed of off-site.
Inspect the tiling battens and underfelt for any defects and notify the Client/Contract Administrator of the findings.
Allow for cutting out and replacing 5.0 linear meters of tiling battens and 1.0 m² of roofing membrane lapped 150mm min to the existing underfelt all around. Include for fitting 1.5m underfelt eaves support tray.
Reinstate the roof covering reusing existing sound tiles supplemented with new matching plain concrete roof tiles secured with alloy clout nails minimum one per tile.
Secure existing adjacent loose tiles with stainless steel tile clips where required. Reinstate the section of rainwater guttering to the correct gradient and ensure all joints are sealed watertight. On completion, remove any debris arising in the roof void together with the protection plywood sheeting.
Remove tubular steel fall restraint barriers around the flat roof and set aside for reuse. Carefully remove the existing rainwater gutters and downpipes and set aside for reuse.
Prepare the existing fibreglass roof surface including grinding down any protrusions to achieve an even surface.
Overlay the existing fiberglass roof surface with 9mm OSB3 Grade boards secured with 50x5mm corrosion-resistant screw fixings at 300mm centres generally and 150mm centres at the perimeter into the roof joists.
Apply Polyroof Protec liquid roofing membrane over the new OSB board strictly in accordance with the manufacturer’s instructions and recommendations as follows:
Surface Prep: Ensure OSB substrate is sound, dry and clean. Primer: Apply Polyroof Uni-Primer DP at 6m²/litre over the OSB substrate Detailing: Fit trims at edges and abutments and treat all details/angles with a coat of Protec resin and 225gsm Polymat embedment. Base Coat: Apply the first coat of Protec Resin (pigmented) to the surface. Reinforcement: Embed 225gsm Polymat into the first coat while wet, ensuring no voids. Top Coat: Apply the second coat of Protec Resin (typically light grey/chromite grey). Finish: Polyfinish, Quartz Sand added to the final coat to allow for pedestrian maintenance traffic.
Consult with Polyroof Advanced Liquid Roofing Technical Department to ascertain that the specification is adequate for obtaining their 30 year product and installation guarantee.
Reinstate the rainwater gutters and downpipes, brackets to be at 1.0m centres max. Ensure the joints of the guttering and downpipes are sealed watertight.
Reinstate the tubular steel fall restraint barriers.
Inspecting and investigating the leak in the flat roof at a service duct penetration through a felt flat roof and notifying the Client/Contract Administrator of the findings.
Include cost for carrying out a appropriate repair to the flat roof covering, including providing a suitable 100mm upstand at the base where the duct interfaces with the flat roof similar to the arrangement shown in this image.
Carry out test on completion to ensure the junction is fully watertight, preventing any further ingress at this location.
Include costs for carrying localised refitting and/or replacement of any damaged, slipped or missing roof slates and tiles.
Copyright in submitted documents remains with their authors. Request removal
View as Markdown