Rubble foundation: hearting solid, chips under a fifth of the volume
Applies only if your house has a rubble foundation.
Why — act while you have leverage
Filling the middle of a rubble wall with chips instead of stone is the cheapest way to build it and the hardest to see. The wall settles unevenly for years afterwards.
What to look at
- Filling stones of a real size, not rubble dust and chips
- A mallet actually in use as stones are bedded
- Chip usage that looks like filling gaps, not like filling the wall
How to check it yourself
The filling in the middle of the wall is rubble not less than 150 mm in any direction, hammered down with a wooden mallet and solidly bedded in mortar. Chips are only for filling the gaps between one stone and the next and, under IS 1597, must not exceed 20 percent of the quantity of masonry. Watch a lift being laid rather than inspecting it after.
Where this comes from: IS 1597 (Part 1):1992 — hearting stones and restriction on chips (indian standard or building code)
More foundation checks
- Photograph before this is covered
- Cover blocks in place — 50 mm to footing reinforcement
- Steel matches the grade and diameter on the drawing
- Concrete cured for at least seven days
- Rubble foundation: through bond stones at every course band
- RCC footing: size and depth as designed, on the correct stratum
- Raft foundation: reinforcement laid in the order the drawing gives and not walked flat
- Pile foundation: pile records kept for every pile, not a sample
- Under-reamed piles: bulb formed at the designed depth
- Plinth beam continuous and tied into the foundation
- Column starter bars plumb, with 40 mm cover and correct laps
- Backfill compacted in layers, not tipped in
- Damp proof course laid unbroken at plinth level