Godwick Hall is seeking contractors to estimate for and complete works for a new roof at Godwick Great Barn in Norfolk.
Address of premises: Godwick Great Barn, Godwick Hall, Mill Road, Godwick, Kings Lynn, Norfolk PE32 2RJ
Contact: Mr James Garner
Telephone: 01328 701948
Re-roofing Barn and associated repairs
Outline schedule of work and specification
Contact for architect’s (PRA) drawings: 1072-201-205 and structural engineer’s
Godwick Hall Barn is listed grade II (List entry Number: 1342509) and part of a Scheduled Ancient Monument
that covers the area of a lost village and the site of Godwick Hall. The existing barn roof has reached the end of
its service life. It is proposed to remove the existing roof finish completely back to rafter level (the east side has pantiles over
plaster and reed, the west side timber shingles with no under-felt), carry out structural repairs and re-roof
with pantiles on both slopes.
Associated repairs such as brick pointing are also proposed. The contractor must
consider whether a temporary roof is required or if the roof can be uncovered and made watertight in
sections; the contractor must also consider safety issues and whether a birdcage scaffold is required internally.
The client does not propose to occupy the interior during the works. General preliminary requirements and
detailed specifications and samples should be agreed with the contractor before entering into any contract.
Proposed roof specification
2.1. Roof tiles
2.1.1. Use new or good quality re-used pantiles. Suitable new pantiles are: William Blyth Barco Pantile,
weathered finish. Provide 6no sample tiles for approval. Tiles are to be hung over battens and every tile nailed
with aluminium clout nails. The existing pantiles are unlikely to be re-usable so assume 100% replacement tiles
2.1.2. Provide left hand verge double roll tiles – available from William Blyth. Bed verges on plain tile
2.1.3. Provide hog’s back ridge tiles – handmade red clay to match ridge tiles. Re-use existing ridge tiles
where possible. Assume 50% salvage. Bed tiles with red handmade clay gallets. Also mechanically fix each tile
with proprietary non-ferrous metal screws and washers. Provide sample of mechanical fixing for approval.
2.1.4. Use hydraulic lime mortars for bedding and pointing tiles such as St Astier NHL 5 natural hydraulic
lime mixed with well graded sharp sand at a ratio of one part lime to 3 parts sand. Provide samples for
2.2. Roofing battens: 50 x 25mm Siberian larch battens, fixed with stainless steel annular ring shank nails,
gauged to suit tiles, min 75mm headlap, 267mm gauge for Barco Pantile.
2.3. Roofing felt and insulation: GLX Gold insulating and breather felt, draped over counter batten, all laps
taped with foil tape to the manufacturer’s recommendations.
2.4. Counter-batten: 50 x 50mm Siberian larch counter battens, fixed over rafters (through ceiling
boarding) with stainless steel screws.
2.5. Ceiling boarding: 44 x 17mm planed Siberian larch battens, fixed into rafters with stainless steel nails,
butt joint battens. Batten also used to close eaves on west elevation – see Architect’s detail 3.
2.6. Levelling pieces over rafters: the contour of the existing roof and existence or not of existing levelling
pieces is not known. There is no intention of flattening the roof out completely; however, some levelling may
be required to allow the roofing tiles lap tightly enough and the roof remain water-tight. Make provisional
allowance for ex 50mm dp x 75mm wide Siberian larch levelling pieces to be scribed over the rafters.
2.7. New oak rafter feet: allow for seasoned oak rafter feet, 125mm wide x 85mm high x 800mm long to
every rafter on the west elevation. Assume rafters @ 400mm c/s fixed to side of existing rafters with stainless
steel coach screws. Refer to Architect’s detail 3. Exact number and spec of fixings to be agreed with the
structural engineer. Assume min 4 no M12 coach screws per rafter foot with min 50mm penetration into
2.8. Closing off west elevation eaves: allow for closing off counter batten zone above rafter feet with a
continuous Siberian larch rail, 50 x 75mm. Final detail, including tilting fillet and mortar bedded eaves tile, to
be agreed with Architect on opening up on site. Refer to Architect’s detail 3.
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2.9. Adaptation of east elevation eaves: allow for a fascia extension to the east elevation to
accommodate the higher roof level. Assume 22 x 93mm treated timber fascia extension to be painted on
treated timber backing. Final detail, including tilting fillet and mortar bedded eaves tile, to be agreed with
Architect on opening up on site. Refer to Architect’s detail 4.
2.10. Closing off eaves internally: allow for infilling gaps where rafters over-sail the wall plate to both west
and east elevations. This is important to reduce drafts and heat loss. Details to be agreed with Architect on
site; assume a 18 x 93mm Siberian larch board is required to be scribed between every rafter on bother west
and east elevations, with treated timber packers to support.
Lead copings and flashings to gables
3.1. Make good the brickwork to north and south gable of the barn before installing protective lead
copings / cappings – see brickwork repairs section below.
3.2. Raise the level of the brickwork with 2 no 50 x 100mm continuous treated C24 timber plates, to be
securely fixed to brickwork of gable. Carry out test fixings with resin anchor fixings. Great care is to be taken
not to split the brickwork. Strapping to the roof side of the gable could also be considered. Use stainless steel
fittings. Refer to Architects detail 1.
3.3. Apply continuous 25 x 50mm Siberian larch drip batten to external face of gable, fixed to plate with
stainless steel screws.
3.4. Provide 18mm marine grade ply top, fixed to plate and batten with stainless steel screws.Top edges
to be rounded. Provide proprietary geotextile underlay for leadwork.
3.5. Line roof side upstand of gable with 18mm marine grade ply. Paint face in contact with brickwork with
black bitumous paint. Secure with stainless steel screw and plugs into brick joints @ min 300mm c/s
3.6. Clad coping with code 6 lead sheet, sheet sizes, laps and clips in accordance with The Lead Sheet
Association recommendations, including a welted drip on the external face of gable. Joints and layout of lead
to be agreed with the Architect on site. Allow for returning the lead and drip at the gable ends. Finish with
3.7. Allow for code 5 lead sheet apron at verges, where roof slopes S1 & S2 meet the gables, sheet sizes,
laps and clips in accordance with The Lead Sheet Association recommendations. The lead flashing is to lap min
75mm under the lead coping and 150mm over the verge tile. Refer to Architects detail. Finish with patination
4.1. On the east elevation, take down and re-fix existing rainwater goods to suit new roof levels. Existing
rainwater goods are black coated galvanised steel by Lindad. Gutters are 150mm half round. Downpipes are
4.2. On the west elevation provide a new gutter (G1) and 2 no down pipes (RWP08 & 09), type of
rainwater goods to match the east elevation. Refer to Architect’s drawing 202.
5.1. Allow for adaptation of the existing below ground drainage to accommodate new runs from RWP08 &
RWP09. Provisional proposals, subject to on site survey of drains, are shown on Architect’s drawing 202. It is
assumed that existing surface water disposal is via soakaways and that these are capable of accommodating
the additional run-off from the west facing slope S1 of the barn. The capacity of existing soakaways is to be
tested on site.
5.2. Allow for 2 no new inspection chambers IC04 & IC05 and 100mm dia drains to connect to existing
chambers. These are to be heavy duty because of the risk of a maintenance vehicle passing over. Provide 2 no
roddable clay access gulleys at the base of the rainwater pipes. Contractor to propose type of IC and gulleys for
5.3. All below ground excavation will be subject to archaeological checks and possibly a archaeological
watching brief – Historic England to confirm.
6.1. The scope of brickwork repairs, shown on Architect’s drawing 205, has been restricted to critical
repairs, generally associated with the re-roofing, structural crack repair (see York-Sill drawings) and the
ornamental brickwork to the west elevation.
6.2. Exact details to be agreed on site with the Architect.
6.3. Brickwork repairs include the top and roof upstand of gables before cladding in lead.
6.4. Bricks to be handmade red clay to match existing, such as Bulmer bricks.
6.5. Use lime putty mortars for bedding and pointing bricks with well graded sharp sand at a ratio of one
part lime to 3 parts sand. Provide mortar and pointing samples for approval. The objective is to match the
existing pointing in colour and texture. All new mortar is to be pointed flush (but allowing for some set back
where arises are eroded) and bagged / brushed to expose aggregate.
Structural repairs. Carry out structural repair works in accordance with structural engineer’s (York-
Sills) drawings 6196/01 P2 and 6196/01 P2.
8. Other repair
8.1. Allow for joinery repair to the shutter at opening D4, west elevation.
Interested parties should require a complete quote in response to the details above by 5pm 7th December 2019, by email to firstname.lastname@example.org. Evidence that the contractor is used to and comfortable working with old listed buildings would be helpful on submission
The successful Tender Response will be determined using Price (70% weighting) and Quality of Service (30% weighting). Quality of Service should be understood as meeting the timescale, completing works according to schedule and to the desired specification.
- Ability to meet the contract
- Availability to deliver within the stated timeframe