Chimney Engineering - Chimney Rebuilds
Chimney rebuilds fall into a few categories and each unique situation will require a different approach depending on budget and feasibility.
In some cases the base of the original chimney is still present through the house. In some cases the chimney remains above the roof but the base, through the house, has been removed. To simply reinstate the chimney with brickwork is not sufficient for safe use, the whole chimney needs to be relined to guarantee continuity of the flue through its entire length.
Where sections of the chimney are missing; rebuilding the structure to its original design and relining its entire length (using the standard reline or unique reline 1 methods shown in our case studies) gives the most favourable results. A different approach would be to reline the existing section of chimney using a stainless steel flexible liner and fill in the missing sections (above or below) using an insulated stainless steel chimney system.
A more frustrating part of our work is to dismantle and rebuild badly built chimneys as set out in our case study below. The ‘normal’ looking chimney was built in the 1980’s and so should meet basic building regulations that have been in force since 1965. The sad reality is, builders and council building inspectors are still allowing the incorrect construction of chimneys. 9 out of 10 new build chimneys we inspect in our area fail basic requirements.
Before installing a stove on a chimney built after 1965 we always insist on a detailed CCTV inspection by an independent professional chimney sweep and here’s why.
This chimney had suffered a devastating chimney fire, caused by a low quality stove that had been used for 10 years. The fire was so fierce that it cracked the internal walls of the house. As we dismantled the chimney it was evident that the damage caused by the fire was because of a number of faults with the chimney construction.
Our mission was to dismantle the entire chimney to its base and remove the affected cracked block wall. By the time we had finished, we had almost entirely reconstructed the gable end of the property. The clay pot liners had been put in upside down allowing running tar to seep through the joints. The joints had been made using ordinary cement (instead of a flue jointing compound) which acted like a sponge sucking up even more tar. All too often we find, as in this case, that the void around the flue has been filled using dust, sand and hardcore, (instead of insulating concrete) once again acting as a sponge. The result was a tar soaked structure that was a ticking time bomb.