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How To Apply Black Jack Roof Coating Help and Advice Roofing

How To Apply Black Jack Roof Coating

Posted on 04 July, 2021

Black Jack 905 is an effective all weather coating for general purpose roofs. The brushable bitumen features added fibres, resulting in a long lasting reinforcing compound that can help repair, seal and waterproof roofing. Black Jack can also be used as a vapour barrier on walls and non-plastic guttering. 

Here, we show you how to apply Black Jack roof coating.

What You Need:

Step 1 – Prepare Substrate

Black Jack can not repair a structurally unsound roof. So before application, make sure that the roofing structure has been inspected. Slates, tiles, sheets and other coverings which are cracked or broken should be fixed or filled. You should also make sure that the area is clean and free from loose debris, dirt, dust, grease and fungi. 

Step 2 – Apply Black Jack Roof Coating

Below we have detailed the different ways in which to apply Black Jack Roof Coating, dependent on the type of roof or surface you are working with. 

  • Applying To Asphalt Roofs

If you are fixing blisters on asphalt roofs, first soften with a blow lamp then smooth out. If the asphalt is crumbling, replace with underlay. Apply 2 coats of Black Jack roof coating with a brush, allowing the first coat to dry before the second. 

  • Applying To Built Up Felt Roofs

First, remove loose chippings. If there are any defects wider than 0.75mm, fill in first with Bitumen Mastic and allow to dry. Any blisters should be opened and cleaned. Apply Black Jack and leave it to go tacky, then bond down the felt. If needed, apply another coat of Black Jack and glass membrane where required. 

  • Applying To Reinforced Concrete

Prep the concrete and allow any new decks to cure first. These can be primed using Bitumen Flashing Primer. 

  • Applying To Lightweight Concrete

If carrying out prep work on lightweight concrete, allow the deck and topping screed to cure first. If applying a glass fibre felt underlay, make sure this is partially bonded using Black Jack Roof Felt Adhesive. Ensure the felt is lapped, sealed and that there is plenty of ventilation underneath. You can then apply Black Jack Roofing Coating and a glass membrane where needed.

  • Applying To Asbestos Cement Sheeting

Ensure the asbestos cement is not saturated before applying any protective coatings. Wait until the cement is fully dry and then apply two coats of Black Jack 905. Make sure the first coat is dry before applying the second coat. 

  • Applying To Metal Surfaces

Any loose rust or signs of corrosion should first be removed. Then, apply phosphate primer to prevent rust from reoccurring. Apply two coats of Black Jack 905 Roof Coating at 1.5 square metres per litre per coat. 

  • Applying To Slates and Tiles

Make sure there are no loose or damaged slates and tiles and that sheets are firmly in place. Apply Black Jack 905 followed by a glass membrane where required.

  • Applying As An All Weather Roof Coating and/Or Scrim Treatment
  1. Apply the first coat of 905 to a clean and receptive surface then apply a glass membrane straight after whilst still wet. 
  2. Ensure there is no air trapped beneath and that the glass is lapped by 50mm to 75mm. 
  3. Paint the inside of each lap with 905. Bridge any small gaps and make sure that the membrane is not pulling too tight. 
  4. Continue sandwiching the glass and roof coating til it measures 150mm vertically. 
  5. Secure using self adhesive flashing whilst allowing 75mm of the flashing to be in contact with the brickwork. 
  6. Apply the second coat of 905 and allow to dry. 
  • Applying As A Final Surface

A third and final coat of 905 is recommended. Apply whilst the film is still tacky and blinded with 1 to 2mm of stone chippings or sand. As an alternative, you could wait 3 days or up to 2 weeks and apply the Black Jack Solar Reflective Paint. 

  • Applying As A Vapour Barrier

Apply two coats of 905 to the warm side of the wall. Make sure to avoid pinholes. Once dry, apply the insulation over the top of it. 

Please Note – Black Jack is not suitable for roof lights, windows or other glass areas. Do not use on areas where solvent contact is likely. Avoid inhalation.

For more info on applying roof coating, speak to one of our team, who will be happy to advise on using any of our products. Or alternatively, take a look at our further range of Black Jack Bitumen Paint and Roofline products. 


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