CONSTRUCTING AN INSPECTION PIT
1 An existing floor can often be cut with a circular saw to add an inspection pit and avoid having to lay a new base, although in the photo shown here, a new base was being laid.
2 After cutting through the concrete base where the inspection pit will be fitted, there should be a layer of hardcore underneath, which will need to be extracted before reaching soil.
3 Digging out the soil isn’t as easy as it looks and can take several hours with a spade. If a digger can be squeezed inside the workshop, it’s best to hire one and save time.
4 Once the hole is large enough, try to ensure the bottom of it is flat, then add a layer of hardcore and concrete to help seal it from moisture collecting inside.
5 If the concrete floor is going to be walked over, it may help to add a ripple effect to it to give some grip, especially if it gets covered in oil and dirt.
6 Walls need to be constructed for the inspection pit. Breeze blocks are being fitted here, with a gap around the outside to fill with concrete to provide waterproof protection.
7 Getting in and out of the inspection pit needs to be considered, whether it’s by a ladder or as shown here, a series of steps with a landing at the top that will be formed with concrete.
8 Once the structure of the inspection pit has been created, it may need to be sealed off to repair the surrounding concrete or as shown here, to make a new base.
9 Finally, painting the inside of the inspection pit white will help with illumination, although it will probably be difficult to keep clean and may need to be redecorated periodically.