Why do balcony drainage bids come in low in Garowe?

Water backing into rooms from a balcony almost always traces back to something the drainage bid never priced. Balcony drainage underbidding risks in Garowe start when a tenderer prices only the visible pipe and leaves out the falls, the outlet, the flashing and the test, so the client pays twice.

What do low balcony drainage bids leave out?

The short answer is the work that is hard to see once the screed is laid. A complete balcony drainage scope includes the screed laid to a fall, the outlet body and its connection through the wall or slab, a flashing or upstand where the balcony meets the wall and door threshold, a trap or grating, and a test. A bidder chasing the job can price the pipe run alone and leave the rest for a variation.

Ask each tenderer for a line-by-line take-off: screed volume and mix, the fall they will build to, outlet type and size, pipe diameter and route, flashing detail, and what test they will run. Compare the lines, not the totals. A bid that shows the pipe but no screed, or an outlet with no flashing, is incomplete.

Why do unrealistic tender allowances survive to site?

They survive because nothing in the tender documents forces the bidder to state the numbers behind the price. If the drawing shows a balcony but no drainage detail, each bidder invents a fall, an outlet size and a rainfall figure. The lowest bidder usually invents the cheapest ones.

Close the gap before award. Ask the project's design engineer or the authority that approves the design to confirm the design rainfall the balcony must handle and whether a ponding test is required. Put the fall, outlet size, pipe diameter and test method in the specification, so every bidder prices the same scope. If the contract allows variations, check what rate applies to extra work and who measures it. Confirm the finished fall and any tolerance against the project specification or engineer, since these are general practice figures, not a local rule.

How do you check a drainage bid before you sign?

Check the bid against the same four things on every tender: fall, outlet, flashing and test. Ask the bidder to show a recent completed balcony whose drainage you can inspect with them. If the bidder claims a completed drainage job, ask for whatever test or inspection record that job produced. Ask two suppliers for written quotes on the outlet and pipe sizes the bid names, so you can see whether the allowance is real.

• Request the drainage take-off with quantities, not a lump sum.
• Ask for the fall in millimetres per metre and the method used to set it.
• Ask for the outlet size and the flashing detail at the door threshold.
• Ask for the ponding test method, duration and who witnesses it.

A bid that cannot answer these is not cheaper, it is unfinished. A bid that answers them at a low price is worth a second look at the workmanship record.

What to do next

Before you award the balcony drainage package in Garowe, send every bidder a one-page schedule asking for the fall, outlet size, pipe diameter, flashing detail and test method, and require a line-by-line take-off with the bid. Compare the schedules side by side, not the totals, and ask the design engineer or the relevant approving authority to confirm the design rainfall for the plot before you fix the specification.