Since the advent of central heating most fireplaces and chimneys have been made redundant, many fireplaces being closed in and chimney maintenance neglected.
However, with the growing realisation that there is nothing like a real fire to bring a room to life, fireplaces are being uncovered and chimneys are being used again.
The chimney is the most neglected area of the house with many heavy chimney pots and large chunks of masonry teetering at the mercy of the elements.
Chimneys can be repaired and restored as original or in some cases removed and rebuilt to the original architectural style.
Renovating / Rebuilding a Chimney.
Sometimes a chimney can lean so much that it has to be removed for safety. This lean is usually caused by the expansion of mortar joints on one side of the chimney stack due to sulphate attack caused by the bricks becoming constantly wet. You will notice that most chimneys lean towards the sun or away from the wind direction.
Scaffolding will need to be erected up to and around the defective chimney before it is carefully dismantled brick by brick to below the existing roof level.
The picture above shows a recent chimney that we removed completely and rebuilt.
Above is a diagram showing the stages of construction.
A. Chimney Pots.
These are available in many shapes and sizes. 25% of each pot is embedded in the masonry below.
The flaunching is made from a waterproof sand / sulphate resistant cement mix.
This sulphate resistant cornicing is designed to shed rainwater out over the brickwork.
These bricks are low sulphate, frost proof, and are exactly the same size as the imperial bricks that were removed. They are laid in a sulphate resistant mortar.
Sourcing bricks the same size as the original will ensure that all the flues are in line.
E. Lead tray.
A code 5 lead tray goes through the mortar joint and turns up into the flue to ensure that all moisture in the brickwork is allowed to move out over the waterproof render beneath.
F. Waterproof rendering.
This is a waterproof sand / sulphate resistant cement two coat render. The brickwork that has been rendered was constructed using some of the existing bricks that were in good condition and have been thoroughly cleaned.
G. Lead flashing.
Code 5 lead flashing.
The combination of the projecting cornice, the lead tray and the lead flashing will ensure that no rainwater will penetrate through the chimney stack.
Any rainwater that falls inside the chimney pots will evaporate providing the flue is well ventilated and has not been blocked off.
Leadwork prepared prior to installation
Chimney under construction
Repairing an Existing Chimney
Existing chimneys can be made safe, durable and efficient by undertaking repair works and general maintenance. Below is a list of the most common repairs that we
If a chimney is leaning less than 1mm in 100mm it is deemed safe. Raking out the existing mortar to a depth of 25mm and repointing with a sulphate resistant mortar will stabilize the lean.
Broken or frost damaged chimney pots can cause smoke blow back so are replaced with new matching pots.
Cracked and loose flaunching allows vegetation to grow. Defective flauching can be removed and replaced with a new sand / sulphate resistant cement flaunching.
Cracks in the projecting cornice can be raked out and filled using special two pack mortars.
Loose and defective rendering is taken off and the brickwork beneath is raked out to a depth of 25mm. Two coats of a waterproof sand / sulphate resistant cement render are then applied.
Defective and loose lead flashings are replaced.
If there are problems with birds roosting between the chimney pots, then we can install bird deterrent spikes. This will not harm the birds, but will prevent them from landing.