I have an apartment where there is a flue in a void approximately 4.5 meters in length. This is the length of the flue from the boiler across the lounge to the outside of the apartment which can be accessed from the balcony.
I believe if I am correct that I may need maybe two inspection hatches (minimum 30cm x 30cm) as there is probably two joins. How do I know if this is the case? or is it better to be safe?
Does it make sense to have one inspection hatch 1.5 meters from the boiler and another 1.5m away from this leaving 1.5m to the outside wall which is accessible from the balcony?
Also, can anyone be so kind as to point me in the right direction to a suitable company to supply and fit these hatches and the approximate cost of this too please?
The apartment is in North London, N11 post code area