THE ESTIMATING ANSWER
For one existing roof opening, start with a defined scope and measurement basis. Measure the structural opening, roof covering type, pitch and interior reveal. Keep unit, manufacturer-matched flashing and interior finish allowance separate. Price the listed tasks separately and state the condition that would require a revision: Rotten curb or incompatible opening changes framing and waterproofing scope.
This guide uses one existing roof opening as a worked, fictional job. Its matching itemized estimate and PDF let you trace the advice to actual document lines. The role considered here is roofing contractor. Confirm the site conditions, product selections and your own costs before preparing a client quote.
Skylight replacement: separate the roof opening from the glazing allowance
A skylight replacement quote should confirm whether the existing opening can remain and identify the exact replacement unit. Record the visible dimensions, roof covering, interior shaft finish and any signs of leakage for the roofer's review. A like-for-like replacement and an enlarged opening are different jobs even when the glazing area looks similar in a product catalogue or a photograph.
Keep the selected skylight, compatible flashing, removal, roof access, fitting and internal making good as separate allowances. Ask who checks the existing surrounding material and how discovered damage will be priced. Interior edge repair, complete shaft redecoration and structural alteration should each be described explicitly; they should not be inferred from the phrase replace one skylight on a quotation.
Share the same roof photographs and opening information with each supplier. Confirm whether product measurement, temporary weather protection and waste removal are included. Compare the full installation scope before comparing the product allowance, and keep any concealed roof damage as a documented change trigger.
A separate worked planning example
Illustrative comparison: one existing opening, one selected replacement skylight and one matching flashing set. Count interior repair as its own measured or fixed allowance. This example does not set an opening size or establish that an old and new product are interchangeable.
Cost and scope questions
Can I quote a replacement using the visible glass size?
Use that measurement only as preliminary information. The installer must confirm the product dimensions, opening and flashing arrangement before selection or fabrication.
Does a skylight replacement include repainting the whole ceiling?
Only when named in the scope. A local interior edge-repair allowance is different from repainting the shaft or the whole room.
1. Define the measured job
Replace one roof window or skylight in the existing suitable opening, with matching flashing kit and interior edge repair. Measure the structural opening, roof covering type, pitch and interior reveal. Record the measurements and existing condition in the estimate before turning quantities into line items. The scope should make clear why this is a separate project from a broader renovation or maintenance quote.
Measurement basis: Measure the structural opening, roof covering type, pitch and interior reveal.
2. Build a product and labor schedule
Keep unit, manufacturer-matched flashing and interior finish allowance separate. This example has 7 distinct lines, including opening and access survey, temporary roof protection, old skylight removal. Use actual supplier prices and labor inputs for a customer job; the displayed amounts are fictional document inputs.
Selections to confirm: Keep unit, manufacturer-matched flashing and interior finish allowance separate.
3. Sequence the work and handoffs
Confirm product and safe roof access before removing the old unit. Show which task depends on access, a selected product or another trade. If that dependency is still open, label the price preliminary and identify the information needed before a firm quote.
Work sequence: Confirm product and safe roof access before removing the old unit.
4. Set a change boundary
Rotten curb or incompatible opening changes framing and waterproofing scope. The example excludes new roof opening, ceiling remodel or concealed structural repair. Record the discovery, agree the revised work and update the estimate before adding it to the job.
If the job changes: Rotten curb or incompatible opening changes framing and waterproofing scope.
Worked project calculation
The example line for opening and access survey is 1 job × $250.00 = $250.00. This line is one part of the complete 7-item estimate and uses a fictional unit rate.
The paired estimate has 7 separate lines. For this fictional job, multiply each quantity by its unit price and add the line amounts to get $3,020.00. The sample PDF uses these exact values, with tax and markup left at zero so the arithmetic is visible. This total is an illustration, not a regional price or an offer to perform the work.
| Cost line | Quantity | Unit price | Line amount |
|---|---|---|---|
| Opening and access survey | 1 job | $250.00 | $250.00 |
| Temporary roof protection | 1 job | $230.00 | $230.00 |
| Old skylight removal | 1 each | $290.00 | $290.00 |
| Skylight unit allowance | 1 each | $1,050.00 | $1,050.00 |
| Flashing kit allowance | 1 set | $270.00 | $270.00 |
| Installation and weathering | 1 each | $620.00 | $620.00 |
| Interior trim and cleanup | 1 job | $310.00 | $310.00 |
| Illustrative subtotal | $3,020.00 | ||
Scope and pricing boundaries
Replace one roof window or skylight in the existing suitable opening, with matching flashing kit and interior edge repair.
Outside this example: No new roof opening, ceiling remodel or concealed structural repair.
Separately identify supplier allowances, labor, subcontracted work and site-specific risk where they apply. Before giving a selling price, decide how your own overhead, profit and any applicable tax will be handled. Do not copy the fictional rates into a real quote without checking your own measurements and supplier or subcontractor figures.
Before you send the estimate
- Measure the structural opening, roof covering type, pitch and interior reveal.
- Keep unit, manufacturer-matched flashing and interior finish allowance separate.
- Confirm product and safe roof access before removing the old unit.
- Rotten curb or incompatible opening changes framing and waterproofing scope.
Read the complete skylight replacement PDF example to see how the scope, individual prices and exclusions appear in a client-facing document. If a condition is still unknown, write that boundary into your estimate and revise the affected line once it is resolved.
Questions about this estimate
Which quantity controls this skylight replacement estimate?
Measure the structural opening, roof covering type, pitch and interior reveal.
When should this skylight replacement quote be revised?
Rotten curb or incompatible opening changes framing and waterproofing scope. No new roof opening, ceiling remodel or concealed structural repair.
TURN THIS EXAMPLE INTO YOUR OWN ESTIMATE
Build a skylight replacement estimate for your project
Use Estimates on iPhone or Android to draft a scope with AI assistance or enter each line yourself. Review quantities, rates, exclusions, and client details before exporting a PDF. The example is free to inspect; some app features may require an in-app purchase.
