Birmingham property stock
1930s Semi Roofs: Concrete Tiles Reaching the End of Their Life
A 1930s semi-detached roof is concrete tile on bitumen sarking, and the sarking is the component that decides when the roof needs replacing rather than the tiles that everyone looks at. Search the terms below, compare the figures for the interwar semi, and book a survey if one applies. Covered on this page: Interwar semi · Bitumen sarking · Concrete tile.
Concrete interlocking or plain tile on bitumen sarking over a cut roof. The tiles are commonly sound in appearance while the layer beneath them has failed, so the deciding component is invisible from outside.
Concrete tile runs 50 to 60 years, so original coverings are now at or past it, and ageing concrete absorbs water and adds load to a structure sized for its original weight.
4 related pages cover this in more depth: concrete tile roof birmingham, roofers sutton coldfield, clay or concrete roof tiles and new build roof problems.
What is a 1930s roof actually made of?
A 1930s semi carries concrete interlocking or plain tiles laid on battens over bitumen sarking felt, on a cut timber roof. Ridge and hip units are bedded in mortar, and the front bay usually has its own small canopy roof.
Perishes and tears, most often above the wall plate where it dressed into the gutter. Commonly sound in appearance while the layer beneath has failed.
Why do the tiles look fine when the roof is failing?
Concrete tiles outlast the bitumen sarking beneath them. The felt perishes and tears above the wall plate while the visible surface stays intact, so the roof leaks and looks sound at the same time.
The feature of the hipped roof is four slopes, long hip lines, no gable verge. The bay canopy has a feature of a small separate roof over the front bay, failing on its own timetable. Ridge and hip bedding shows mortar releasing units along long hip lines.
What does the bay canopy add?
The bay canopy is a separate small roof with its own covering, its own junction against the main wall, and its own life cycle. It commonly fails before the main slopes and is routinely left out of quotations.
The loft conversion has a prevalence of common in this stock, altering insulation and ventilation requirements. The concrete tile has a service life of 50 to 60 years, so original coverings are now at or past it. Ageing concrete absorbs water and adds load to the original structure.
Does a hipped roof cost more to recover?
Yes, somewhat. Four slopes need scaffold to four elevations, and long hip lines carry mortar-bedded units along their whole length. Both add labour compared with a gabled roof of the same floor area.
The chimney is usually one or two stacks, frequently now redundant. Sarking condition is visible only from inside the void.
- Bitumen sarking perishes above the wall plate, while the tiles stay sound.
What changes if the loft has been converted?
A converted loft makes the roof a thermal element enclosing habitable space, which changes the insulation and ventilation requirements at recovering. It also frequently involves altered structure that needs checking before work starts.
- The bay canopy fails on its own timetable.
- Long hip lines carry more mortar-bedded units than a gabled roof.
- Ageing concrete absorbs water and adds load to the original structure.
The only way to see it is from inside.
What the void inspection looks for
The deciding component is invisible from outside, so an external assessment of a 1930s roof is close to worthless. It fails independently and is routinely omitted from quotations covering the main slopes.
Getting the sarking checked
Four-sided roofs carry long hip lines with mortar-bedded units along all of them, so ridge and hip work is a bigger share of the job. Ageing concrete absorbs water and gains mass, which matters when assessing a structure sized for its original weight.
Sarking, and 5 more
- sarking
- hipped roof
- bay canopy
- wall plate
- interlocking tile
- cut roof
An interwar semi carries concrete interlocking or plain tile on bitumen sarking, and a hipped roof gives it four slopes, long hip lines and no gable verge at all. Two things follow. Mortar bedding along those long hips releases units, and the sarking beneath perishes and tears — most often above the wall plate, where it is least visible. The tiles commonly look sound while the layer under them has already gone. The bay canopy is a separate small roof failing on its own timetable, which is why it has to be priced as its own item rather than assumed into the main slope.
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