# Re-Roofing Decision Table — 92 m² House

Three quotes: A (slate, £14,200), B (concrete tile, £11,650), C (slate, £16,900).
All figures below are as quoted. Where a cost is unstated, it is flagged rather than assumed.

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## 1. True total cost

| | **Quote A** | **Quote B** | **Quote C** |
|---|---|---|---|
| Headline price | £14,200 | £11,650 | £16,900 |
| Scaffolding | Included | **+ £1,400** (separate) | Included |
| Waste removal | Not stated — **ask** | Not stated — **ask** | Included |
| **Known landed cost** | **£14,200** | **£13,050** | **£16,900** |
| Cost per m² | £154 | £142 | £184 |
| Gap vs cheapest | +£1,150 | — | +£3,850 |
| Open cost risk | Waste/skip, VAT status | Waste/skip, VAT status, "about" £1,400 is not a fixed price | Lowest — most inclusive quote |

**The headline spread of £5,250 is really £3,850 once scaffolding is added back.** B's £2,550 apparent advantage over A shrinks to £1,150 — about 8% — for a materially different roof.

## 2. Cost against what you actually get

| | **Quote A** | **Quote B** | **Quote C** |
|---|---|---|---|
| Material | Slate (type unconfirmed) | Concrete tile | Slate (type unconfirmed) |
| Typical material service life | 80–100 yr natural slate; 30–40 yr fibre-cement imitation | 40–50 yr | 80–100 yr natural slate; 30–40 yr fibre-cement imitation |
| Cost ÷ guarantee years | £1,183/yr | £2,610/yr | £845/yr |
| Cost ÷ expected roof life (if natural slate / concrete) | ~£178/yr | ~£261/yr | ~£211/yr |

On cost-per-year-of-cover, B is the **worst** value of the three by a wide margin, not the best. It is only the cheapest cheque.

## 3. Risk

| | **Quote A** | **Quote B** | **Quote C** |
|---|---|---|---|
| Guarantee length | 12 yr | 5 yr | 20 yr |
| Guarantee type | Workmanship — the firm's own promise | Workmanship — the firm's own promise | **Insurance-backed** |
| Survives the firm going bust? | **No** | **No** | **Yes** (subject to policy terms) |
| Deposit | **40% = £5,680** | 25% = £2,913 (of £11,650) | **£0 until work starts** |
| Cash unsecured before work | **£5,680** | £2,913 | **£0** |
| Deposit as share of your exposure | High — 40% is above the normal 10–25% range | Normal | None |
| Weather/exposure risk | Low — 3 weeks out, short lead | Low — but next week means little time to verify anything | Moderate — 9 weeks out risks working into worse weather, depending on season |
| Main risk to you | Large unsecured deposit; guarantee dies with the firm | Shortest cover on the shortest-lived material; scaffolding priced "about" | Paying a £3,850 premium for cover you may never claim on |

**The two risks worth real money here are the £5,680 deposit and the guarantee type.** A 12-year workmanship guarantee is worth 12 years only if the firm survives 12 years; a large share of small building firms do not. C's insurance-backing is the only promise on the table that outlives the company.

## 4. Timing

| | **Quote A** | **Quote B** | **Quote C** |
|---|---|---|---|
| Earliest start | 3 weeks | Next week | 9 weeks |
| Delay vs fastest | +2 weeks | — | +8 weeks |
| Read on it | Healthy — busy but not booked solid | **Suspiciously free.** Good roofers are rarely idle | Booked out — usually a sign of demand, but 2 months of exposure if the roof is already leaking |

If the roof is actively leaking, C's 9-week wait has a real cost: temporary repairs, interior damage, possibly a tarp through a storm season. Price that in before comparing.

## 5. Scorecard

| Criterion | Weight | A | B | C |
|---|---|---|---|---|
| True cost | High | Good | Best | Worst |
| Material longevity | High | Best | Worst | Best |
| Guarantee strength | High | Fair | Worst | Best |
| Deposit exposure | Medium | Worst | Fair | Best |
| Timing | Medium | Best | Best | Worst |
| **Overall** | | **Strongest balance** | Cheapest cheque, weakest value | Safest, most expensive |

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## What I'd pick

**Quote A — conditional on two things: the slate being natural slate, and the deposit coming down to 25% or being structured as materials-on-delivery.**

The reasoning:

- **B is a trap dressed as a saving.** Once scaffolding is added it is only £1,150 below A, and for that £1,150 you accept a shorter-lived material and a guarantee that expires in 5 years. On cost per year of cover it is more than twice as expensive as A. The "can start next week" is not a bonus — for a 92 m² re-roof it usually means an empty diary.
- **C is genuinely the lowest-risk option and I would not argue with anyone who chose it.** Zero deposit and a guarantee that survives insolvency are worth real money. But £2,700 over A is a steep premium for 8 extra years of cover on a roof that should last 80, and 9 weeks is a long time to wait with a roof you have already decided to replace. **Pick C instead of A if:** the roof is not leaking, you plan to sell within a few years (a transferable insurance-backed guarantee is a selling point), or a large deposit to a small firm is something you simply will not do.
- **A sits where the value is** — real slate, a guarantee that covers the period when workmanship faults actually show up (bad flashing and ridge work fail in years 1–5, not year 18), and a sensible lead time. Its single genuine flaw is the 40% deposit, and that is negotiable.

**If A refuses to move on the 40% deposit, switch to C.** Handing £5,680 to a firm whose guarantee dies with it, when a zero-deposit alternative exists, is the one version of this decision I would not defend.

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## Before you sign — ask all three

**Ask first, because it can invert the whole table:**

1. **Is this price inclusive of VAT?** A 20% difference dwarfs every gap above. If one quote is ex-VAT and another inc-VAT, the ranking changes completely. Get it in writing.
2. **Is 92 m² the roof area or the house footprint?** A pitched roof is typically 15–40% larger than the floor plan. Confirm each firm measured the same thing, or you are comparing three different jobs.
3. **What is included for the parts nobody quotes for:** battens, felt/breather membrane, new underlay, ridge tiles, flashings, gutters, fascias, chimney work? "Re-roof" means different things to different firms.
4. **What happens if you open it up and the timbers are rotten?** Get the day rate or the per-rafter rate for unforeseen work *now*, in writing, not mid-job.
5. **Waste removal and skip permits — included or extra?**
6. **Public liability insurance certificate and confirmation the scaffolding is certified and inspected.**
7. **Two addresses of slate/tile jobs done 5+ years ago that I can drive past.** Recent work proves nothing about workmanship.
8. **Payment schedule tied to stages** (strip / felt-and-batten / cover / completion) rather than dates.
9. **Written start and completion dates, and what happens if you overrun.**

**Quote A specifically:**

- Is this **natural slate or fibre-cement/reconstituted slate**? Which quarry or brand, what thickness? This is the single biggest unknown in your whole comparison — imitation slate at £154/m² is poor value; Welsh or Spanish natural slate is good value.
- **Why 40%?** If it is genuinely for materials, will you accept 25% now and the materials balance on delivery to site, with me seeing the supplier invoice?
- Is the 12-year guarantee **written, and does it cover materials as well as workmanship?**
- Are you insured or bonded such that my deposit is protected if the business fails?
- Is the guarantee **transferable** if I sell?

**Quote B specifically:**

- Is the £1,400 scaffolding a **fixed price or an estimate**, and who is liable if it stays up longer than planned?
- **Why is next week free?** Has a job fallen through?
- Which concrete tile, and what is the manufacturer's own material warranty — is it longer than your 5 years?
- Would you extend workmanship cover to 10 years, and at what price? (Their answer tells you a lot about their confidence.)
- Has the **roof structure been checked for the load**? Concrete tile is significantly heavier than slate — if the house was built for slate, this needs a structural opinion in writing.

**Quote C specifically:**

- **Who underwrites the insurance-backed guarantee, and can I see the policy document and the exclusions before signing?** Ask specifically what is *not* covered and whether there is a claims excess.
- Is the certificate **issued at completion** and is it **transferable on sale**?
- Natural slate or imitation — same question as A, quarry and thickness.
- **Is 9 weeks firm or could it slip to 12?** What is your position if my roof leaks in the meantime — will you do a temporary repair, and at what cost?
- Given you are £2,700 above the next slate quote, **what is in your price that theirs lacks?** Make them itemise it.

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## One last check

Ask each firm for the **same written specification** — material and brand, membrane, battens, fixings, flashings, waste, scaffolding, VAT, unforeseen-work rate — and get all three to re-quote against it. Three quotes for three different jobs is not a comparison. That one email is worth more than any table, including this one.