infa red measuring for chimney lengths

[Petefinny]

im seeing if anyone uses them infa red measuring devices for checking the length of a chimney for lining sizing , does any body use them or what other methods are best for quick sizing a liner

 

[Ermintrude]

Drop a but of string down or shove up flue brushes- preferred as you can do it from the floor. How the hell would you use ir or sonic up a bendy flue? You ever seen inside a chimney? Left then right then left then it's..... Blocked

 

[Petefinny]

reply from outside, stand at the bottom of the chimney breast then point it at the chimney and it should tell you the length, well that's my theory, wether it will work or not is another story, just tryin to find a quick solution without gettin ladders out

 

[Best]

If the chimney is all finish brick, from ground up, then count the brick! For example - 3 brick with joints 300mm so count how many 3 course of brick & multiply by 0.3 of a metre.
Not joking, that's what I have done before, but for a liner there will be extra for angled parts & bends & it will be a bit of a guess to add on to the height, so not a good way unless chimney is near vertical or only has a couple of short turns.

 

[Ermintrude]

Using it outside is a bit of a gander as you would need to use some trig. If you want to do it outside get an old theodolite. Measure elevation angle and horizontal distance. Use some trig. Or best bet get a Trimble 8 series robotic reflector less station £20k ish and it will work it to the mm. I just push brushes up.

 

[lame plumber]

as mentioned, string and weight fm the top plus 1/2 metre, keep it simple, after all you need to check condition of chimney before you get working on it anyhow