Chimney Repairs Heswall

Chimney Work in Heswall

Heswall is built up the side of a hill and then along the top of it. Between the Lower Village and the ridge at Telegraph Road the ground climbs hard, and the houses climb with it — Victorian and Edwardian villas built deliberately high for the view over the Dee, big interwar detached houses on long sloping plots, and later development running out through Gayton, Pensby, Barnston and Thurstaston.

Two things follow from that, and they both land on the chimney. The first is exposure: there is very little shelter on a west-facing slope above an estuary, and the wind arrives with a clear run at whatever is standing highest on the roof. The second is height. These are tall houses with steep roofs, and a flue has to finish well clear of the ridge to draw at all, so the stacks were built long — often a couple of metres of brickwork above the tiles before you even count the pots.

The work on this page is roofing work: repointing, re-forming flaunching, renewing lead aprons, soakers, stepped flashings and back gutters, pots, cowls and bird guards, part rebuilds, and taking a stack down to roof level. What we do not do is line or sweep a flue or sign off an appliance; that belongs to a HETAS or Gas Safe registered installer and a chimney sweep, and we will say so rather than take on work that is not ours. Roofs and ridges around the stack come under roof repairs.

Height, Wind and How a Tall Stack Is Held Up

Above the roof line a masonry chimney is a cantilever with nothing bracing it. It is held upright by its own weight and by the strength of the bed joints, and that is the whole of it. Wind pushes on the broad face, the stack tries to pivot about the point where it leaves the roof, and every joint near that level is put alternately into compression and into tension. Mortar is good at the first and poor at the second, which is why a tall stack is almost always at its weakest within two or three courses of where it comes out of the slope.

That is also why proportion matters more than age. The approved guidance that sits behind the Building Regulations puts a limit on how far an unrestrained masonry chimney may stand above the highest point where it meets the roof — broadly, no more than about four and a half times its own smallest width — and plenty of the tall stacks on this hillside were built to the edge of that, or have been pushed past it by a later course or a taller pot. A slim stack that has been made taller is a slim stack with a longer lever on it.

When a stack is over that proportion, or when the joints near the roof line have gone soft, there are three honest routes and the survey decides which. The first is to reduce it: take off the top courses, re-form the head and fit a shorter pot, which costs the flue a little draught and buys a great deal of stability. The second is to rebuild the upper section properly, off sound brickwork, over a damp-proof tray, in a mortar that suits the brick. The third is restraint — a steel stay or bracket set fixed from the stack back into the roof structure — and that one is not a decision to be taken on the roof, because it puts load into rafters and purlins that were never asked to carry it. Anything of that sort, like anything below roof level, is a matter for Building Control and a structural engineer, and we will tell you when you have reached that point.

What to Look At After a Rough Night

A stack on this ridge tells you about a gale the morning after, if you know where to look. Stand back and check the pots against each other: on a stack with more than one, a pot that has gone out of line with its neighbours has moved in its bed. Then look for a fine dark line following a bed joint near the roof, which is the joint that takes the bending, and for lead that has pulled away from its chase on the windward side while the sheltered side sits tight. Debris is the other tell — lumps of flaunching or mortar in the gutter, on a flat roof over a bay, or on the lawn directly below.

Two Heswall habits are worth checking at the same time. Aerial and satellite poles are very often lashed to the stack because it is the highest fixing available, and a two metre pole in an exposed wind works on the brickwork like a spanner, so the strap points are a good place to find cracked joints. And a tall stack that is no longer serving anything is sometimes quietly carrying a television aerial and nothing else, which is a poor reason to keep two metres of unrestrained masonry standing above a roof on an open slope.

Getting to the Stack in Heswall

Sloping ground changes the scaffold before it changes anything else. Standards on a hillside plot have to be levelled and stepped with base plates and sole boards rather than simply stood on the grass, and on a steep garden the lift heights on one side of the house will not match the other. Add mature gardens — the beech, holly and rhododendron that come with this part of the Wirral — and the route from the gate to the gable is often the thing that takes the longest to work out.

Getting the materials there matters too. The lanes running off Telegraph Road and down towards Thurstaston are narrow, some drives are long and steep, and a scaffold wagon cannot always reach the house, so tube and boards get carried the last part by hand. Exposure then feeds back into the design: a tall scaffold on an open slope needs more ties and less sheeting than the same scaffold in a sheltered street in Bebington, and it is built for the wind it will actually stand in.

Leadwork, Pots and Cowls in Heswall

A tall stack usually sits high on a steep roof, and that shape puts a large back gutter behind it. Lead expands and contracts a long way in sunshine, so a gutter or a flashing run in a single unbroken length will buckle and then split along the fixings; the pieces are therefore kept short and lapped, and the lead is chosen heavy enough for its size and its exposure. On a steep pitch the soakers do most of the quiet work under the slates while the stepped cover flashing, chased into the beds and wedged, takes the weather. Where an aerial bracket has been bolted straight through a flashing, that hole gets dealt with properly rather than sealed over.

At the top, the hill itself causes a problem that catches people out. When the ground behind a house rises higher than the chimney does, wind coming over the slope rolls down onto the roof and pushes back down the flue, so a fire that draws perfectly in a still week smokes in a westerly. That is an air-flow problem rather than a blocked flue, and the answer is usually an anti-downdraught pattern cowl rather than anything more drastic. A plain rain cap or a bird guard will not touch it, which is why it is worth knowing which fault you actually have before anything is bought.