News From the Roof Top

By Dave Rayner, Ye Olde Soot Sweepers, Ltd.

Why inspect chimney from the roof top?

When a fireplace and chimney are swept, we do it from in front of the fireplace. In this way we can monitor the amount of deposit that falls into the firebox and sweep slowly if the chimney is dangerously dirty to ensure that soot does not fly all over the room.

We check the condition of the firebox floor and wall panels for cracks and/or warping. We check damper operation and sliding mesh fire screens for warping and operation. We inspect up the flue from inside the firebox to check for warping and or distortion of the inner flue.

The problem with inspecting the flue from the bottom is that most fireplace chimneys have an offset or bend and therefore we cannot see the entire chimney unless we also inspect from the top.

The roof top inspection includes checking outer casing of chimney for rusting or perforation. We check the roof flashing or pan flashing seal to the chimney on chase box. We remove the rain cap and examine down the flue.

When looking down the chimney flue we are looking at the lining joints, both vertical and horizontal. If we see warping, this is a concern. This indicates extreme temperature or chimney fire.

When a chimney fire occurs the flue lining is heated very quickly which causes it to expand. Once the fire is over, the flue lining will have wrinkles in numerous areas or the vertical seam may split. Once this happens the insulation in the chimney will settle into these voids thus leaving no insulation at the top of each effected section of chimney, creating a hot spot.

The other items we are looking for are dented chimney sections. Dented sections are a result of handling at time of installation or from shipping. The dent is caused by a blow to the exterior casing hard enough to push the inner flue lining inwards.

When a chimney section is dented severe enough – from the outer casing through and dents the inner lining, it can create four possible problems.
  1. The insulation between the outer casing and the inner lining will have been compressed and/or separated at this point. This creates a conductive element in this area thus creating a "hot spot" on the chimney.
  2. The denting of the outer casing and inner lining may also affect the coupling of the chimney section, which may allow heat and smoke leakage at the joints.
  3. The result of the denting of the inner lining may separate vertical joints or at least distort the female end, which would allow insulation to trickle out at this point.
  4. The specifications and requirements of the ULC Standard S610 or ULC Standard S604 Product Safety Standards for this type of chimney type require continuous inner dimension and outer dimension. Once this is jeopardized, such as a dent in the side of the chimney, this would restrict the flow and would deem this chimney as "unsafe" and does not meet the manufacturing standards.

The National Fire Protection Association states:

"Chimneys, fireplaces and vents shall be inspected at least once a year for soundness, freedom from deposits and correct clearance. Cleaning, maintenance and repairs shall be done if necessary."

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For more information on having your chimney, fireplace and vents inspected and/or cleaned, contact:

Dave Rayner, Certified Master Chimney Sweep

Ye Olde Soot Sweepers, Ltd. at 475-7896

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