Padstones and beam bearings explained
A steel beam is only as good as the thing it sits on. Padstones are the least glamorous part of a steel job and the part most likely to cause a problem on the morning of the lift.
What a padstone actually does
The end of a loaded beam pushes down onto a very small area of wall. Ordinary block or old brickwork will crush under that pressure, so a padstone, usually a dense concrete block or a cast in situ pad, spreads the load over enough masonry to carry it safely.
The engineer sizes the padstone from the reaction at the beam end. It is a calculation, not a rule of thumb, which is why substituting whatever block is on site is not acceptable.
Bearing length
Bearing length is how far the beam sits onto the padstone at each end. Too little and the load concentrates dangerously at the edge. Irish practice commonly sees 150mm as a minimum for domestic work, but the engineer's figure governs, and long spans or heavy loads need more.
This also affects the steel order. A beam is cut to the clear span plus the bearing at both ends, so if the opening measurement is wrong the beam is wrong. We always ask whether the dimension given is the structural opening or the finished opening.
The mistakes that cost a day
The three we see most often are padstones set at the wrong level so the beam does not line up with the ceiling, padstones too short so the bearing is inadequate, and padstones not cured before the beam is landed on them. All three are avoidable with a check against the drawing before delivery is booked.
It is also worth confirming that the temporary propping is in place and adequate before anything is removed. That is the builder's responsibility, but it is the reason a delivery gets turned away.
How we help
When we quote from an engineer's drawing we flag the bearing assumptions we have cut to, so the builder can confirm the padstone positions match. It takes a minute and it prevents the expensive version of the conversation.
Send us the drawing and the measured opening, and we will confirm the cut length before the steel is touched.
Want this priced for your own job? Send us your drawings or a photo and we will come back with a fixed price, usually within one working day.
Common questions
Need this done properly? Talk to the workshop.
Send us drawings, a sketch or a site photo. We come back with a fixed price and a firm lead time, usually within one working day.