In brief
- A low plaster bid often omits preparation work such as hacking, dust removal, dampening and the scratch coat rather than cutting the finish itself.
- Plaster preparation underbidding risks in Qardho show up later as hollow sounding areas, drummy patches and loss of adhesion.
- Before signing, ask for the preparation steps in writing and walk a recently plastered wall with the supervisor.
Contents
A low plaster bid in Qardho usually leaves out preparation, not finish. When a tenderer prices plaster as one lump per square metre, hacking, dust removal, dampening, curing water and the scratch coat can quietly fall outside the rate. The finish still looks complete on handover. The bond between mortar and block is what suffers, and that is where plaster preparation underbidding risks in Qardho begin.
What work disappears from a low plaster preparation bid?
Preparation is the part of the plaster scope that carries labor and water but leaves nothing visible, so it is the easiest line to drop. In general practice, a plaster build-up starts with a scratch coat keyed into the background, followed by the floating and finishing coats, with each coat dampened and cured before the next. A bidder chasing the lowest number can price only the finishing coat over a dry, dusty wall. Check the tender for separate lines for surface preparation, hacking or keying, and curing. If the bill of quantities lumps everything into one plaster item, ask the estimator to break it down in writing. Ask the municipal engineer's office what method or records it holds for plaster works, and compare that with what the bid actually covers.
How does skipped preparation turn into loss of adhesion?
Loss of adhesion starts at the interface between mortar and block, and it is driven by dust, dryness and coat thickness. Dust and loose sand on the block face stop the mortar from gripping. A dry block pulls mixing water out of the mortar before it can set, so the coat sits on the surface instead of bonding. Thick single-coat application makes shrinkage worse and opens the bond. In hot, dry conditions, walls may dry fast and curing water can disappear quickly unless someone plans for it, so confirm the local drying pattern with the supervisor or the project engineer. Test records, if the contractor keeps them, should show mix proportions and curing. Walk a recently plastered wall and tap it with a light hammer or the handle of a trowel. A hollow, drummy sound points to a patch that has separated from the background. Confirm acceptance criteria against the project specification or engineer before you reject work.
How do you close the gap in the tender and on site?
Write the preparation steps into the scope so they cannot fall out of the rate. Name hacking or keying, dust removal, dampening of the background, scratch coat and curing as separate items, each with its own quantity and method statement. Require the contractor to hold a small trial panel and get it approved before plastering starts, and make that panel a payment milestone. During the work, the supervisor should check the background is damp and clean before each coat, and that curing water is actually being applied, not just promised. Ask two suppliers for written quotes for the plaster materials you need, and ask the contractor for its own cost build-up, so you can see whether the rate covers preparation time. Keep the accepted method statement on site and compare the work against it.
What to do next
Before signing any plaster subcontract in Qardho, ask the bidder to submit a one-page breakdown that lists hacking, dust removal, dampening, scratch coat and curing as priced items. Walk one recently plastered wall with that bidder and tap for hollow areas. If the breakdown is missing or the wall sounds drummy, reprice the preparation work before you award.
Local reporting: this article is written for building work in Qardho and Puntland. Ground conditions, prices and rules differ between places; confirm the details for your own site.