Everbuild Black Jack 903 Bitumen Trowel Mastic

Unit price per



Everbuild Black Jack 90 Bitumen Trowel Mastic is for sealing and filling holes in mastic asphalt, roofing felt, corrugated iron, concrete, timber, slates, metal guttering and downpipes.

Price Includes VAT

Everbuild Black Jack 903 Bitumen Trowel Mastic

  • Fast drying
  • Fibre-reinforced
  • Suitable for use with all bituminous surface coatings
  • Remains flexible for long periods after application

Coverage: 2 litres per m² (giving 2mm wet thickness)

Everbuild Black Jack 903v Bitumen Trowel Mastic is a trowel applied black heavily filled bituminous compound with added fibres for reinforcement. The product forms a surface skin, but the mass below remains soft to allow for moderate movement. 

Everbuild Black Jack 903 Uses

Adheres to/fills holes in:

  • Mastic asphalt
  • Roofing felt
  • Corrugated iron
  • Cast iron
  • Fibre cement
  • Slates
  • Lead, copper, zinc
  • Concrete
  • Timber

Mainly used for:

  • Waterproofing, stopping, bedding, bonding and sealing

How To Apply Everbuild Black Jack 903

EVERBUILD BLACK JACK 903 BITUMEN TROWEL MASTIC is ready for use and should not be thinned.

Apply by steel trowel or putty knife.


Force the compound into the crack, but finish with a 25mm band at a 3mm thickness running the length of the crack. For large cracks and holes, apply the compound over the area to be treated and embed a closely woven glass fibre membrane into the compound to overlap the crack or hole by 50mm. Allow to dry and then apply a second coat, fully covering the reinforcing membrane.


Tighten loose hook bolts and trowel around with mastic. Remove loose screws, re-bed screws and washers in EVERBUILD BLACK JACK 903 BITUMEN TROWEL MASTIC and tighten. Top seal in further mastic and trowel to a smooth finish. If the sheet is cracked, clean and prime with BLACK JACK BITUMEN FLASHING PRIMER and apply a bandage strip of glass fibre embedded in the mastic. When dry, overcoat with BLACK JACK BITUMEN /FLASHING PRIMER followed by BLACK JACK BITUMEN PAINT. Use the same technique for sealing side and end laps in corrugated sheeting.


Point up butt edges of ridge tiles, fillets and slates with EVERBUILD BLACK JACK 903 BITUMEN TROWEL MASTIC.


Trowel over cracks and pinholes, where necessary, reinforcing with a woven glass membrane, fully embedded and covered.


Re-adhere loose felt using BLACK JACK ROOF FELT ADHESIVE. Apply EVERBUILD BLACK JACK 903 BITUMEN TROWEL MASTIC and overcoat with BLACK JACK ALL WEATHER ROOF COATING. Note: felt must be completely dry before applying the mastic.

Everbuild Black Jack 903 Bitumen Trowel Mastic Data Sheet


    Delivery within 2-5 days.  

    BANK HOLIDAY: Next working day orders are dispatched on working days. Orders placed before 3pm Thursday will be dispatched Friday. After 3pm Thursday orders will be dispatched Tuesday for delivery Wednesday. 




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    Next Working Day

    (Order before 3pm for same day dispatch)

    Under 2kg £4.95 £4.95 £7.95
    Up to 30kg £6.95  £18 £10.95
    30kg - 50kg £11.95 £25 £16.95
    50kg - 100kg £18.95 £37.95 £27.95
    100kg+ £45 £90 Not Currently Available
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    Next working day delivery available on IN STOCK products.

    Out of stock products will be delivered next working day from when they are received into the warehouse. 


    Next Working Day Delivery Example

     Order placed Monday 11:30am Dispatched Monday pm Delivery Tuesday
    Order placed Monday 4:30pm Dispatched Tuesday am Delivery Wednesday
    Order placed Thursday 11:30am Dispatched Thursday pm Delivery Friday
    Order placed Thursday 4:30pm Dispatched Friday am Delivery Monday


    Click and Collect

    Click and Collect available within one hour on orders placed between 8am and 3:30pm Monday to Friday (excluding Bank Holidays).
    Orders placed outside of this time will be available within the next hour during the above slots. 
    You will receive an email when your order is ready to collect. 
    Collection Address: Unit 28, Ripley Business Park, Ripley Dr, Normanton Industrial Estate, Normanton WF6 1QT
    *If you live in a restricted area and would like to query your shipping cost please call our customer service team (01977 876116) and they will be able to give you a personalised quote. 
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