Three bids with widely different prices for the same project? The gap between the highest and lowest can reach tens of per cent, and the reason is usually not that one is genuinely cheaper, but that each contractor priced something different: one excluded insulation, another assumed lower-quality materials, and a third priced items below cost to recover them later through change orders. Comparing contractor bids properly starts before the bids arrive, not after. This guide explains how to set a common basis before tendering, how to evaluate bids technically and financially, contract clauses that protect the owner, and the regulatory dimension in the permit journey.
Before Tendering: Set a Common Basis
- Complete construction drawings for all disciplines.
- Clear specifications for materials and finishes.
- A single bill of quantities that everyone prices.
- A written scope of work: what is included and what is excluded.
- The required construction period and clear payment terms.
Technical Evaluation
- The contractor's experience on similar projects, and visiting them.
- Technical staff and equipment.
- The proposed schedule and how realistic it is.
- Financial standing.
- Classification and regulatory records.
Financial Evaluation
- Compare item by item, not the total.
- Identify items priced below cost, a source of later change orders.
- Review exclusions and qualifications.
A Model Comparison Table
| Criterion | Suggested weight | What is evaluated |
|---|---|---|
| Price after normalisation | High | The total after adding exclusions |
| Experience | Medium | Similar completed projects |
| Technical staff | Medium | A qualified site engineer and technicians |
| Schedule | Medium | Realistic duration and sequence |
| Standing and guarantees | Medium | Ability to finance and continue |
Weights vary by project; what matters is setting them before opening the bids.
Contract Clauses That Protect the Owner
- A payment schedule linked to actual progress. Read: Progress reports and releasing payments
- Clear delay penalties.
- A change order mechanism.
- A warranty period and retentions.
- Compliance with the approved drawings and no pouring without the supervisor's acceptance.
The Regulatory Dimension
In the Balady building permit journey, the building contractor is designated within the contracting stage and notified to accept the assignment and complete their details. So deciding on the contractor early prevents permit delays. Read: Building permit steps on Balady.
Common Mistakes
- Tendering on preliminary drawings.
- Comparing totals without normalising exclusions.
- Choosing the cheapest bid without visiting their work.
- A contract with no schedule or penalties.
These are causes of delay and overruns. Read: Causes of construction delays.
Frequently Asked Questions
Should I choose the cheapest bid?
Not before verifying the pricing is complete and the contractor is technically and financially capable.
Who prepares the bill of quantities?
The engineering office or project manager, from the construction drawings.
How many bids should I request?
Three to five bids from pre-qualified contractors is usually enough for comparison.
Should I negotiate with the lowest bidder?
You can after normalisation, but avoid pressure that pushes them to cut quality.
Does design and build remove the need to compare?
No, evaluating the offer remains important. Read: Design only or design and build?.
How Abak Engineering Consultancy Helps
Abak is an accredited engineering office in Riyadh that prepares bills of quantities and specifications, tenders the project, compares bids technically and financially, and reviews contract clauses to protect the owner. See our engineering project management service, or contact us.
Regulatory information is based on the Balady platform and the Ministry of Municipalities and Housing, and procedures may be updated by the competent authority. Last reviewed: October 2026.