Basic Fitting Details No. 1

Transcription

1 No. 1 Fixing free edges of flashings A. Clips for flashings over interlocking tiles B. Clip to ridge or hip roll C. Clip to apron flashings Clips should be made from quarter hard copper, 0.6mm thick, terne coated or stainless steel 0.38mm thick. Turn the clips over by at least 25mm. X Soft copper only X 50 Copper or stainless steel X X All flashings should be secured against the risk of wind lift. Position fixing clips at between mm centres depending upon the degree of exposure to wind. X = For moderate to severe exposures additional fixings should be positioned at not more than 75mm from the free edge. Secure clips with copper nails. Step and cover flashings and secret gutters A. Step and cover flashing to profiled tiles Hall Clip at each step Water line mm Note: No flashing piece to exceed 1.5m in length. B. Abutment step and cover flashing with secret gutter Use BLM Copper Strip or Permastrip. Turn the clips over by at least 25mm C. Abutment flashing with secret gutter Continuous (for single step) flashing Lap to suit roof pitch. See lap diagram on page 18 of BLM s Product Brochure Edge clipped to suit exposure using Copper Strip or Permastrip 15mm MAX 65 Welt 75

2 No. 2 Soakers and step flashings Cover flashings A. Soakers 75 A. Cover flashing to felt roof upstand L 100 Size of soaker L = gauge + lap + 25mm Top edge turned over tile Note: No flashing piece to exceed 1.5m in length. 100 Hall Clips at 450mm centres. See page 8 of BLM s Product Brochure. Lap Gauge 75 B. Marking-out step flashing Hall Clip at every step For pointing details see pages 8 and 9 of BLM s Product Brochure B. Cover flashing to asphalt upstand BLM Building Paper to separate flashing from asphalt Supporting fillet Edge clipped to suit exposure using Copper Strip or Permastrip mm MAX Water line Note: No flashing piece to exceed 1.5m in length. Hall Clips at laps and 450mm centres. Turn clip 25mm over the Lead leaving at least 6mm for expansion of Lead C. Cover flashings, roof pitches up to 3º Minimum upstand 100mm maximum 200mm Codes 5 and MAX length between laps Clips at 200 to 450mm centres depending on exposure 75mm 100-mm lap joints

3 No. 3 Chimney flashings A. Bossed apron Edge clipped to suit exposure using Copper Strip or Permastrip. Use Hall Clips at 450mm centres. See page 8 of BLM s Product Brochure. B. Welded apron Roof pitch Gusset 25mm 75mm Front apron in position Width of chimney 100mm mm upstand -200mm apron Cut Fold for turn-in Apron flashings A. Apron flashing over slates or tiles Lap to suit roof pitch. See page 18 of BLM s Product Brochure. Edges clipped to suit exposure. Use Copper Strip or Permastrip. 75mm mm 100mm Hall Clips at 450mm (approx) centres. See page 8 of BLM s Product Brochure Note: No flashing piece to exceed 1.5m in length. Cut Fold Gusset leadwelded C. Side flashing Varies to suit type of slate or tile. Mark the steps out to suit the joints in brickwork. See page 21of BLM s Product Brochure D. Bossed back gutter * Minimum upstand Fold Cut Leadwelded gussets Gussets E. Welded back gutter F. Back gutter fixed Roof pitch 500mm (approx) Cover the top edge of the back gutter with a cover flashing 200 mm sole 100mm upstand 200 Width of chimney ===== Cut Fold Use Hall Clips at 450mm centres. Minimum 3 Hall Clips.

4 No. 4 Ridge and hip flashings A. Ridge saddle at abutment B. Ridge saddle at the top of a valley Width of ridge board Lead welded Roof pitch 25mm welt Bossed Allow 175mm Lead welded joint Mark out steps to suit joints in brickwork. See page 21of BLM s Product Brochure Welded Gusset C. Fixings at top of each hip flashing Wood Roll Saddle may be bossed for shallow pitches or welded for either shallow or steeply pitched roofs. Welted edge Ridge tile F. Cross section D. Edges clipped to suit exposure. Use Copper Strip or Permastrip. No ridge flashing to exceed 1.5m in length Code 4 and 2m length for Codes 5,6,7,and 8. *Roll fixed 5mm () above slate line Lap to suit roof pitch. See Lap diagram page 18 of BLM s Product Brochure E. Wood Roll Roll end normally splayed G. Roll end bossed or leadwelded mm mm Lap to suit roof pitch. See Lap diagram page 18 of BLM s Product Brochure

5 No. 5 Pitched valleys A. Details Double row of copper clout nails Saddle Additional head fixings for pitches above 60º in top third of each side only. Mortar bedding on plain tile slips Welt Lap length to suit pitch of the valley. See Lap diagram page 18 of BLM s Product Brochure Note: No flashing piece to exceed 1.5m in length. For cross sectional dimensions. See Fig B below. B. Dimension key A 125mm 2250mm 75 25mm clear channel A With bedded tiles With unbedded tiles or slates Width of Lead to Width of Lead to line valley line valley (mm) (mm approx) (mm approx) (mm) (mm) For information on the sizes of pitched valleys in relation to catchment area, it is essential to refer to Rolled Lead Sheet The Complete Manual published by the LSA.

6 No. 6 Drips and rolls A. Box gutter drip D. Tapered gutter details 75mm Fixing along upper third of bay only Raking cut essential Drip height 50mm. See table 1 page 7 Undercloak fixed to Wood Roll for top of bay only B. Tapered gutter drip Wood Roll carried to edge of drip Copper nails spaced at 50mm centres 100mm E. Standard wood cored roll with splash lap Cross section of wood cored roll 3-5mm Raking cut essential Drips in gutters may be fitted without splashings Turn up 165mm for overcloak Turn up 75mm for overcloak C. Roll drip intersections for wide gutters Normal roll detail with splash lap may be used. See Figs E and F. Roll carried to the edge of the drip and normally splayed 40mm Standard wood cored roll with splash lap Wood Roll Wood cored rolls are suitable for all roofing and cladding applications Nail the roll undercloak at the top third of the length only using Copper Nails at 50mm centres Wood Roll 5mm Roll detail for Codes 6,7 and 8 - edge cut to within 3-5mm F. Drip (up to 3º) See table 1 page 7. Roll details for Codes 4 and 5 - edge folded under copper clips 55-60mm. See table 1 page 7 Undercloak extended 50-60mm 40mm splash lap Copper Nails spaced at 50mm centres

7 No. 7 Parapet and tapered gutters A. Cross section of parapet gutter 50mm For details of maximum sizes. See table 2. B. Measurement of girth C. Cross section of box gutter 75mm Upstand 225mm Sole mm 225mm MAX 100mm 75mm Table 1 Gutter drip heights BS EN Minimum drip Code No height (mm) 4,5 50 Where there is and 6 no roll to drip intersection Table Gutter dimensions BS EN Maximum Maximum Code No length overall girth between (see section drips above) (mm) (mm) D. Cross section of tapered gutter Tilting fillet Minimum width at lowest point

8 No. 8 Fixing flashings Cleaning joints With existing joints, all this mortar must be removed Brickwork When removing mortar from an existing joint it is important to remove ALL the mortar to a depth of at least 25mm. Joints over 18mm wide Stainless steel screw, washer and plug Lead Sealant Masonry Lead Flashing Wide joints over 18mm will require a more substantial fixing. It is recommended that stainless steel screws and washers are used at 450mm centres on flashing lengths of no longer than 0mm. The joint should be pre-pointed with mortar and then pointed with BLM Lead Pointing Sealant. Joints over 20mm wide should comprise half mortar and half BLM Lead Pointing Sealant, the nozzle should be cut at an angle and the sealant applied to both the top and bottom of the joint once the mortar at the rear of the joint has set. Joints under 18mm wide Hall Clip Sealant Mortar Brickwork The joint should be at least 6mm wide to allow Hall Clips to be inserted to hold the Lead flashing in place before pointing in with BLM Lead Pointing Sealant. Joints with a DPC DPC Sealant Brickwork 25mm (min) 50mm (min) Joints below a DPC can often cause problems if they are not fitted correctly. On new buildings the Flashing can be inserted during construction, using a single welt to hold it in position. A batten, the same height as the joint and 25mm wide may be used to support the DPC until the mortar has set. The batten is then removed leaving a clean void for pointing with BLM Lead Pointing Sealant. If the DPC is too low, it may be necessary to cut another chase in to the brickwork to allow the flashing to be fitted correctly. Helpful Hints Always ensure joints are thoroughly cleaned and no mortar remains Individual flashing lengths should not exceed 0mm Joints under 18mm wide should be held firmly in place with Hall Clips Using Hall Clips instead of Lead wedges will help to prevent the easy theft of Lead flashings Use at Least 1 Hall Clip per step when fitting step flashings Use 1 Hall Clip at 450mm centres and where flashing pieces overlap when fitting linear flashings Joints over 18mm wide require stainless steel screws and washers Use BLM Lead Pointing Sealant to point in the Lead in to the masonry Ensure joint is completely dry before applying the sealant Cut the Sealant nozzle to suit the width of the joint Minimum depth of the sealant should be no less than 10mm The face of the sealant can be smoothed using a wet pointing tool