We render the chimney head above the roof and the chimney in the attic and rooms with a breathable, non-combustible render that suits old brick. Before that we check that the masonry under the render is sound, because render will not save a crumbling head. Describe in the form where the chimney needs rendering and what you see.
When rendering helps and when it does not
Rendering helps if the bricks are sound and hard but the joints have crumbled, the surface is porous or the masonry has small, shallow cracks. Render keeps rainwater out and protects the joints from frost. Rendering is also a way to restore old render that has come off in pieces.
Rendering does not help if the bricks are crumbling and loose, the head is leaning or a crack runs through the full thickness of the masonry. Then chimney head rebuilding is needed first, and rendering can follow. Nor does render close cracks inside the flue channel: if smoke comes through them, the solution is a liner or rebuilding. If the masonry is damp from condensation inside, render on it will come off until the cause is dealt with: condensation in the chimney.
Rendering the chimney head above the roof
Above the roof, render has to withstand frost, rain and temperature swings. We use lime-cement or a special chimney render that lets vapour through. Hard cement render on old, soft brick is a mistake: it does not let moisture out, water builds up behind it, freezes, and the render comes off together with the brick's surface layer. To make the render hold, we embed a reinforcing mesh in the surface. At the top the chimney needs a crown slab with an overhang, otherwise water gets behind the render along the top edge.
Rendering and whitewashing a chimney in the attic
In the attic a chimney must be light in colour. The fire safety regulations require the flue and the wall it is in to be whitewashed or painted a light colour in the attic. On white masonry, dark soot streaks show at once where flue gases are escaping through a crack. So before whitewashing we seal the cracks and crumbled joints, and we record the damaged spots. This requirement does not apply to metal flues.
In the attic we do not put foam or any other combustible material on the render, and around the chimney we keep the required distances to timber structures. If dark streaks appear again on whitewashed masonry after the heating season, there is a crack in the flue, and it must be inspected with a camera: camera inspection.
Cabinet Regulation No. 238 “Fire Safety Regulations” of 19.04.2016, point 83: in the attic the flue and the wall containing the flue are whitewashed or painted a light colour; the requirement does not apply to metal flues. Regulations checked 04.11.2026; from 2 January 2027 they will be replaced by new fire safety regulations, which we will check as soon as they are adopted. Source: likumi.lv, checked 04.11.2026.
How chimney rendering is done
- Cleaning and inspection We clean the flue and inspect it, so we do not render over damage that needs a different fix.
- Preparing the surface We remove old, loose render, rake out crumbled joints and fill them with mortar.
- Mesh and render We dampen the surface, embed a reinforcing mesh and apply the render in an even coat.
- Paint and whitewash Above the roof we coat the render with vapour-permeable paint if needed. In the attic we whitewash the chimney or paint it a light colour.
Rendering is done in frost-free weather, because render does not set in frost. The work is done by a qualified craftsman.
How much does chimney rendering cost?
The price depends on the area to be rendered, the height of the chimney and access to the roof or attic, the condition of the old render and joints and whether mesh, paint or whitewashing is needed. It also depends on whether we clean the flue and fit a cap on the same visit. Materials are priced separately from the labour. The specialist will name the price after you submit the form and after the inspection, before the work. Other prices: prices.