Building a house is the biggest investment most Kenyans will ever make. Yet many first-time builders make avoidable mistakes that cost them hundreds of thousands of shillings — or worse, result in unsafe structures. Here are the 10 most common mistakes and how to avoid them.
1. Building Without Approved Plans
Starting construction without county-approved architectural plans is illegal and extremely risky. You could face:
- Demolition orders from the county government
- Heavy fines and penalties
- Inability to get a title deed for the completed house
- Problems selling or financing the property later
Solution: Always hire a registered architect, get proper drawings, and submit them for county approval before breaking ground. Read our step-by-step building guide for the full process.
2. Hiring an Unregistered Contractor
Many homeowners hire the cheapest contractor they can find, often one without NCA registration. This leads to poor workmanship, project delays, abandoned projects, and no legal recourse when things go wrong.
Solution: Only hire NCA-registered contractors. Verify their registration, visit past projects, and sign a detailed contract. Find contractors on JengaHub.
3. Not Having a Proper Budget (or Ignoring the BOQ)
Starting to build with a vague budget like "I have KES 3 million" without a detailed Bill of Quantities (BOQ) is a recipe for an unfinished house. Many people run out of money at the finishing stage because they didn't plan properly.
Solution: Get a detailed BOQ from your architect before starting. Add a 15–20% contingency for unexpected costs. Check our cost breakdown guide for realistic estimates.
4. Buying Cheap or Counterfeit Materials
Saving money on materials sounds smart until your foundation cracks because of adulterated cement, or your roof leaks because of thin iron sheets. Counterfeit building materials are a serious safety hazard.
Solution: Always buy from verified suppliers. Check for the KEBS mark on all materials. Compare prices on our price list so you know what's reasonable.
5. Not Doing a Soil Test
The type of soil on your plot determines your foundation design. Building on black cotton soil, fill soil, or waterlogged ground without proper testing can lead to foundation failure — the most expensive and dangerous structural problem.
Solution: Hire a geotechnical engineer to do a soil test before designing your foundation. It costs KES 30,000–80,000 but can save you millions in repairs.
6. Paying the Contractor Too Much Upfront
Giving your contractor 50–100% of the money before work is done is one of the most common ways people lose money. Once paid in full, some contractors slow down, cut corners, or disappear entirely.
Solution: Structure payments around milestones:
- 20–30% deposit to start
- Payment after foundation completion
- Payment after walling completion
- Payment after roofing
- Final 10% retention after finishing and snag list
7. Making Changes During Construction
Changing your mind mid-build — moving a wall, adding a room, changing window positions — is extremely expensive. Every change means tearing down work already done, buying new materials, and paying extra labour.
Solution: Finalize your plans completely before construction starts. Spend extra time reviewing the architectural drawings. It's far cheaper to change a drawing than to demolish and rebuild a wall.
8. Not Supervising the Construction
Handing everything to your contractor and never visiting the site is asking for trouble. Without supervision, contractors may cut corners — using less cement in the mix, fewer steel bars, or thinner columns.
Solution: Hire a clerk of works (site supervisor) or visit the site regularly yourself. At minimum, have your architect or structural engineer inspect at key stages: foundation, ring beam, roof structure.
9. Ignoring Waterproofing and Drainage
Many builders skip or minimize waterproofing to save money. Within a few years, they face rising damp, leaking roofs, and water damage that costs more to fix than proper waterproofing would have cost in the first place.
Solution: Invest in proper DPC (damp proof course) at the foundation, waterproof your bathroom floors and walls, and ensure proper drainage around the house. These are not optional extras — they protect your entire investment.
10. Underestimating the Finishing Phase
The most common reason houses sit unfinished in Kenya is that owners spend all their money on structure and have nothing left for finishing. Finishing (plastering, tiling, painting, fixtures, cabinets, external works) typically costs 30–40% of the total build.
Solution: Budget for finishing from day one. Your BOQ should include finishing costs. If you're building in phases, set aside money for finishing before you start each structural phase.
The Bottom Line
Most construction mistakes come down to three things: poor planning, cutting corners on quality, and lack of supervision. Invest in a good architect, hire a registered contractor, use quality materials from verified suppliers, and stay involved throughout the process. Your future self will thank you.
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