Should Chimney Work Be Done During a Re-Roof?

A stack is often the tallest point of the roof, and working on it needs a safe platform. On a re-roof the scaffold already stands around the house, so the stack can be reached without hiring a second set.

Does a shared scaffold save money?

It can. For a three-bedroom semi, HomeBuilding gives scaffolding at approximately £1,000 including permits, as a typical UK figure (HomeBuilding, Sep 2025). Putting it up once for the whole roof avoids paying for the same job twice. It also means the licence period, if one is needed, runs once and not twice.

A scaffold that blocks part of a pavement or road falls under the highway authority's licensing. Under Somerset Council's rules, applying for the permit is the appointed contractor's task, not the householder's, and the fee is £124.60 for each 28-day period (Somerset Council, April 2026) with at least 10 working days' notice. Devon County Council words its own rule differently, since it has the scaffolding company make the application for its customer. The answer on scaffolding for chimney repairs covers the options in more detail.

Flashing is the name for the lead dressed across the junction of chimney and slope. Soakers, small pre-bent pieces of lead, run under each slate or tile beside the stack, and a back gutter, the little channel behind it, carries water round to the slope on either side.

Why replace lead when the covering is new?

Lead is cut and bent to suit the covering beside it. New slates or tiles sit at a slightly different level from old ones, so lead bedded to the previous roof can end up too short, lifted or split. Lead flashing "can last for over 80 years" (MyJobQuote, Sep 2026), so new lead fixed now can outlast the new roof.

A leak at the chimney is the usual complaint after a re-roof where old flashing was reused, and it tends to show first around the back of the stack, where water collects. Keeping the old lead saves little and risks a return visit, with scaffold, to put right a fault that could have been cured first time.

MyJobQuote gives a typical UK range of £350 to £920 for full chimney leadwork, depending on scaffold (MyJobQuote, Sep 2026). If a gale has already hit the stack, that damage is dealt with before the new covering goes on around it.

A re-roof gives the closest look at a stack that you are ever likely to get. From the scaffold, the pointing, crown and pot can be inspected at arm's length and photographed for you.

What gets checked?

The pot is tested for movement by hand, and the bed it sits in is looked at for gaps. The flaunching is examined for cracks. The joints are probed for crumbling mortar and the bricks for splits. In the loft, the part of the stack inside the roof space is looked over for damp. If the survey finds trouble, you decide on the repair there and then, with the photographs in your hand.

Small jobs such as repointing or renewing the crown are simple to add. A stack that leans or has cracked through is a bigger decision, which is discussed under cracks in a chimney stack.

A stack can look perfectly good from the street and still be tired. The top courses tend to hide what a roofer sees up close, such as hollow joints, hairline splits and a pot bedded on little more than habit.

The timing is straightforward when it is planned in advance. The stack is repaired first where possible, then the flashing and soakers go in as the new covering is laid around it.

Does the order matter?

Yes. Doing any repointing or rebuilding before the lead goes on keeps mortar and brick dust off a clean covering. Lead is fixed into the brickwork, so the joints should be sound before it is chased in. Scaffold stays up until the lead is finished and the stack has been checked, so any snag found at the end can be fixed without a return trip.

If a stack is to be removed or reduced, consent questions come first; see planning permission to remove a chimney. A chimney on a shared wall also brings in the Party Wall etc. Act 1996, which needs two months' notice for notifiable work.

Ask for the stack to be included when the roof is surveyed, and ask what each stage will involve. You get photographs of both, and one written price that covers the roof and the stack together. The other work on stacks is listed under chimney repairs.