Brandon Roofers carries out full chimney rebuilds for homeowners in Bury St Edmunds, using materials chosen to suit your existing stack and give you a result that lasts.
A chimney rebuild is not a job where one set of materials suits every property. The age of the stack, the type of brick used originally, the pitch of the roof, and whether the chimney is still in use all affect what the right specification looks like. Choosing the wrong mortar or the wrong brick type is a mistake that does not show up immediately - it shows up two or three winters later when the new work starts to crack or the bricks blow.
We work across Bury St Edmunds and the wider area from Brandon, carrying out full chimney rebuilds with new flashing, pointing, and mortar flaunching to the pot. Here we explain the material choices in plain terms so you can have an informed conversation before work starts.
Where possible, the new brickwork should match the original in colour, texture, and size. This matters for appearance, but it also matters structurally. Older properties were commonly built with handmade or machine-made bricks that are softer and more porous than modern engineering bricks. Mixing brick types in a chimney stack can cause moisture to migrate toward the softer brick, accelerating damage.
Salvaged or reclaimed bricks are often the best match for an older stack, and a reputable roofer will source them where the job calls for it. New bricks manufactured to match period styles are also available, though the colour match is not always exact. On a modern property where appearance is less critical, standard wire-cut bricks are perfectly appropriate.
One question worth asking any contractor: where are the replacement bricks coming from, and have you seen them against the existing stack? A vague answer is a warning sign.
Mortar choice is probably the single most important material decision in a chimney rebuild, and it is the one most often got wrong. The basic rule is that the mortar should be no harder than the brick it is bonding. If mortar is harder than the surrounding brickwork, any movement in the stack is absorbed by the brick rather than the joint - and bricks crack, while mortar can be repointed.
Older stacks - typically anything built before the mid-twentieth century - were usually laid with a lime-based mortar. The correct repair mortar for these is a lime-based mix. Using ordinary Portland cement (OPC) mortar on a lime-built stack is a common error. The cement mortar is far harder than the original brickwork, and it will cause the softer bricks to crack and spall as the stack moves with temperature and moisture changes.
Modern stacks built with harder bricks can use a standard cement-based mortar. The correct mix ratio matters too: a mortar that is too rich in cement will be too rigid; one that is too weak will erode quickly at the exposed joints of a chimney.
A sand-and-cement mortar with a ratio around 1:3 to 1:4 (cement to sand) is suitable for most modern stacks. A hydraulic lime mix - NHL 3.5 or NHL 5 - is generally appropriate for older stacks, with the specific grade depending on the exposure and the original brickwork.
Lead flashing is the standard material for sealing the junction between a chimney and a roof, and for good reason. Code 4 or code 5 lead is durable, easy to dress around angles and protrusions, and - when fitted correctly - has a long service life. It is the material most roofers will specify for a chimney rebuild, and in most cases it is the right choice.
The pros of lead flashing: it is malleable, long-lasting when properly installed, and universally understood by roofers and surveyors alike. The cons: it is expensive relative to some alternatives, and it is occasionally targeted by thieves on exposed properties, though this is less common on a chimney than on a porch or bay window.
Lead-free alternatives such as aluminium flashings or self-adhesive bitumen-backed flashing tapes are available. These are cheaper and sometimes used in repairs. For a full rebuild, however, properly fitted lead flashing is the correct specification. Adhesive tape products are generally a temporary repair solution, not a permanent one, and they do not perform as well in the long run at chimney junctions, which are subject to significant movement.
Flaunching is the sloped mortar collar around the base of the chimney pot. It directs water away from the top of the stack and holds the pot in place. The correct flaunching mix is a firm mortar - typically a 1:3 cement-to-sharp-sand ratio - shaped to a smooth, sloped finish that sheds water cleanly.
Flaunching is often one of the first things to crack on an older chimney because it is fully exposed and subjected to freeze-thaw cycles. When it fails, water gets behind it and into the core of the stack. On any chimney rebuild, the flaunching is replaced as standard rather than simply patched.
If pots are being retained, they should be checked for cracks before being reset. A cracked pot is worth replacing at this stage, as the scaffold is already up and the incremental cost is small.
Whether the flue is active affects the specification. A chimney that is still in use - with an open fire, log burner, or gas appliance - requires the flue to remain open and correctly lined. If the flue liner is damaged, the rebuild is the right time to address it. A flexible stainless steel liner can be installed through the rebuilt stack before the pot is set.
A chimney that is permanently out of use can be capped during the rebuild. The pots are removed and a vented cap is fitted over the flue opening to prevent water ingress while allowing the flue to breathe. Sealing a flue completely without ventilation can cause damp to build up inside the stack.
The right answer depends on what is actually wrong with the stack. A roofer who has accessed the chimney from scaffolding and inspected all four sides is in a position to give you a clear recommendation. One who quotes from the ground is not.
The cost of a full chimney rebuild depends on the size of the stack, the height of the property, the materials specified, and whether scaffolding needs to be hired independently. A single-flue stack on a two-storey house will generally cost significantly less than a large double-flue stack on a three-storey property. Your specific quote will depend on what the roofer finds on site.
Lead flashing typically fails because the lead has oxidised and cracked over years of exposure, because the mortar joints holding the stepped flashing have eroded, or because the original installation was poorly done - for example, the lead was surface-fixed rather than properly dressed into the mortar bed. Thermal movement over many years also causes lead to fatigue at folded edges.
We work on properties of all ages and types across Bury St Edmunds and the wider area around Brandon. Older stacks need lime-compatible mortars and sympathetically matched bricks. We discuss the correct specification with you before work starts.
If you need a chimney rebuild in Bury St Edmunds, call Brandon Roofers to arrange for us to assess the stack from scaffolding and give you a clear, itemised quote. We will explain what materials we are using and why, so you know exactly what you are getting.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
