A roof replacement estimate is a best reading of a roof you can only partly see. The shingles are visible from the ground and the ladder, but the deck underneath them is not, and neither is the way the house was built decades ago. When the old roof comes off and the wood underneath turns out to be spaced boards, rotted sections or full of old nail holes, the scope of work can change, and the number on the estimate can change with it. Knowing why that happens, and how code upgrades and your policy's Ordinance or Law coverage fit in, helps you read any roof replacement estimate with clear eyes.
Key takeaways
- A roof replacement estimate is based on what can be seen before tear-off. The deck, framing and hidden damage often can't be confirmed until the old roof is removed.
- A "redeck" means replacing or covering the wood under the shingles so it is solid and flat enough to hold a new roof. It is one of the most common reasons a scope changes.
- Code upgrades are changes a building code requires when a roof is replaced. Whether a policy pays for them depends on the policy, so read yours and ask your agent.
- Ordinance or Law coverage is a policy feature that generally relates to the extra cost of bringing a repaired or rebuilt home up to current code. Many homeowners don't know whether they have it.
- Ask for the estimate in writing, with a line for decking, so a change in scope is explained, photographed and agreed to before the work continues.
What does a roof replacement estimate actually cover?
A solid roof replacement estimate should spell out the parts of the job you are paying for. At a minimum, look for these:
- Removal of the existing roof covering and disposal of the old material
- The type and brand of shingle (or other roofing material), including color
- Underlayment, the layer between the deck and the shingles
- Flashing, vents, drip edge and ridge components
- Any known decking repair or replacement, and how it is priced if more is found
- Cleanup, and how the work is scheduled around weather
What an estimate cannot do is show you the condition of the wood underneath the shingles. A careful contractor will look at the attic from the inside, check the roof edges, and note things like soft spots, but the full condition of the deck is usually only confirmed once the old roof is off. That is the gap where estimates tend to change.
What is a redeck, and when does a roof need one?
Redeck is short for replacing the roof deck, the layer of wood that the underlayment and shingles are fastened to. In the field, we use it two ways. Sometimes it means tearing out sections of the deck that are damaged or rotted and replacing them. Sometimes it means covering the entire existing deck with new sheathing so the surface is solid and even.
A roof may need a redeck when:
- The existing deck is made of boards with gaps between them (more on that below), which is not a good base for modern shingles
- Parts of the deck are rotted, delaminated, or stained from years of slow leaks
- There are a lot of old fastener holes or damage left by earlier roofs
- The deck is uneven, so new shingles would not lay flat
- A repair, addition, or fire or water damage changed the structure and framing needs to be rebuilt first
In our practice, some of our bigger jobs are more than a re-roof. On a house with an addition or fire damage, we may have to redo framing before there is anything solid to put a roof on. That kind of work is why we tell customers up front that a roof can be a different job once we see what is underneath.
Why does spaced decking matter?
Many older homes in Oklahoma have what roofers call space decking or plank decking: boards, often 1x4s or 1x6s, laid with gaps between them instead of a continuous sheet of plywood or OSB. It was a common way to build when the roof covering was wood shakes, which need air to dry out. Our owner, Jeremy Hays, has said that Oklahoma was the first place he ever really ran into space decking. Where he started roofing in Texas, he says, it was always plywood.
Shingles are made to sit on a solid, flat surface. Building codes and most shingle manufacturers generally call for a continuous deck under asphalt shingles, and a gap-filled deck can leave shingles unsupported between boards and nails with little to hold onto. That is why a house with space decking often needs a plan for the deck before the shingles go on. The usual approach in our practice is to overlay the existing boards with sheets of OSB or plywood, so the new roof sits on a solid surface without ripping off the whole old deck.
It is also why a roofer who has only walked the roof may not know what he is dealing with. Space decking is easy to see from the attic with a flashlight, and a good estimate process includes that look.
OSB vs. plywood roof decking: what do we see in practice?
Both oriented strand board (OSB) and plywood are widely used as roof sheathing. They are made differently: plywood is thin layers of wood veneer glued in alternating directions, and OSB is compressed strands of wood bonded with resin. Here is how they compare from a roofer's point of view.
| Plywood | OSB | |
|---|---|---|
| What it is | Layers of wood veneer glued together | Compressed wood strands bonded with resin |
| Typical cost trend | Has been the pricier option lately, according to our crews | Often the more economical choice |
| Handling | Familiar to most roofers | Familiar to most roofers |
| Moisture exposure | Generally tolerates getting wet during a job | Edges can swell if it stays wet, so keeping it covered matters |
| What we use most | Less often these days because of price | Our usual choice on redecks lately |
A few honest notes on this table. First, material prices move around, so which one is cheaper changes over time. Jeremy has said that plywood has been "insanely overpriced" lately, which is why OSB is what his crews put down more often now. Second, neither one is a shortcut: the point is a solid, properly fastened deck. Third, the building code and the shingle maker's instructions are what set the requirements, not a roofer's preference, so ask what grade and thickness is going on your roof and why.
What happens when the old roof comes off?
This is the moment the estimate gets tested. Here is the order of events on a typical job where a deck problem shows up:
- The old roof comes off. The crew strips the shingles and underlayment down to the deck.
- The deck gets inspected. The crew looks for rot, soft spots, gaps, broken boards and old damage. When we pulled one old deck, we saw hundreds of holes from nails, old fasteners and years of repairs. Jeremy's view is that holes like that are exactly what a roof needs to have dealt with, not buried under new shingles.
- Photos are taken. Before any repairs are covered up, the condition of the deck is photographed so the homeowner and, if there is a claim, the insurance company can see what was found.
- The scope is discussed. If the deck needs more than the estimate allowed for, the contractor should explain what was found and what it means for the price before going further.
- The deck is repaired or covered. Damaged sections are replaced, or the deck is overlaid with new sheathing.
- The roof is built back. Underlayment, flashing, shingles and the rest go on.
The photographs in step 3 matter on any job, and especially on a job that involves an insurance policy. A deck that can't be seen after the shingles are on is difficult to prove later.
What counts as a roof code upgrade?
A code upgrade is a change that building codes require when a roof is replaced, even though the old roof may not have had it. A building code is the set of safety and construction rules a city or county adopts. When a roof is replaced, the work can trigger current code requirements for things like:
- The condition and type of the roof deck
- Underlayment and flashing details
- Drip edge, ventilation and ice or water barrier requirements, where they apply
- Fastening patterns
We say it often: code is code for a reason. The rules exist so a roof holds up when the weather does its worst, and roofers who ignore them end up with callbacks. What exactly applies to your house depends on the city or county you live in, the code they have adopted, and the local inspector, so it is worth asking your roofer which requirements apply to your permit and how they will be documented.
A related point: some code upgrades are the contractor's call and some are the inspector's. If your project requires a permit, the city's requirements are the baseline, whatever the estimate says.
What is Ordinance or Law coverage?
Ordinance or Law coverage (sometimes called building code compliance coverage) is an optional feature in many homeowners policies. In general terms, it is meant to help pay for the added cost of meeting current building codes when a covered loss means a home has to be repaired or rebuilt. Without it, a policy may pay to put back what was there, and the difference to bring it up to current code can fall on the homeowner.
Jeremy's take, after years of reading policies alongside homeowners, is that "nobody knows what this stuff means in an insurance policy," and that it can change the outcome of a claim. We would add one important caution: policies differ a lot. Whether yours includes this coverage, what limit it carries, and how it applies to a roof, are all questions for your policy documents and your agent. We can tell you what a roof requires. We can't tell you what your policy owes.
Why it matters for decking
Decking is one of the places where code and coverage meet. If the deck under an old roof does not meet current requirements, bringing it up to standard is a real cost. Whether a policy pays for that is a matter of its wording and its coverages, and homeowners should expect that different insurance companies and different policies can reach different answers. A good habit is to ask your agent, before a storm, what your policy says about code upgrades, and to keep the answer in writing.
How do estimates and supplements change, in general?
Contractors use a few different terms for changes, and it helps to know them:
- Change order. A written agreement between you and your contractor to change the scope or price of the work.
- Supplement. An additional request, often sent to an insurance company on a claim, for costs that were not in the first estimate, such as hidden damage found during tear-off. Whether a supplement is accepted is up to the insurance company and the policy.
- Allowance. A set amount in an estimate for work that cannot be priced exactly in advance, such as decking repair.
- Unit price. A stated price for extra work, such as a price per sheet of decking, so that a surprise has a number attached before anyone is surprised.
Here are some common reasons the estimate changes, and what a transparent contractor does about it.
| Reason for a change | What it often looks like | What good practice looks like |
|---|---|---|
| Rotted or damaged deck found | Sections of wood are replaced | Photos, a count of sheets or boards, a written change order |
| Spaced decking | The deck is overlaid with new sheathing | Explained before work starts, priced per sheet or area |
| Code requirement identified | An added component or a different fastening method | Citation of the requirement and the permit note |
| Framing or structural problem | Rafters or framing are repaired | Photos and a clear explanation of the cause |
| Weather delay | Tarping and reschedule | Communication, and no price change for a delay you did not cause |
What does a clear roof replacement estimate process look like?
If you want fewer surprises, here is a process you can ask any roofer to follow:
- Inspect the roof surface and the attic. The attic view shows the underside of the deck, which is the best preview of what is below.
- Write down what you see. Notes should mention the deck type if visible, any staining or soft spots, and the age and layers of the existing roof.
- Put decking in the estimate on purpose. Include either a stated allowance or a unit price for extra deck repair.
- Explain the codes that apply. Ask which permit and inspection requirements are expected.
- Agree on photo documentation. Photos of the deck before cover-up go to you.
- Confirm changes in writing. Any change to scope or price is agreed to before work continues.
- Do a final walk-through. The finished roof and the cleanup are reviewed together.
What questions should you ask your roofer?
Bring these to the estimate:
- Have you looked at the deck from the attic, and what type is it?
- Do you expect to redeck, and if so, with what material and thickness?
- What is the price for extra decking beyond what is in the estimate?
- Which code requirements apply to my permit, and who confirms them?
- How will you document what you find after tear-off?
- What is your plan if it rains while the roof is open?
- What will you do if the work is bigger than we expected?
What are the most common mistakes homeowners make?
- Comparing estimates on price alone. Two numbers can look far apart because one includes decking and one does not.
- Skipping the attic. The underside of the roof is where you can see a lot of the truth about what is going on.
- Assuming the estimate is a final price. An estimate based on a partial view can change. A written change process is what protects you.
- Not reading the policy until after a loss. Coverage for code upgrades, deductibles and limits are easier to understand before a storm than during one.
- Letting hidden work go undocumented. If the deck is covered before anyone sees it, nobody can show what was there.
Frequently asked questions
Why did my roof replacement estimate change after the work started?
Usually because something was found that could not be seen before the old roof came off, such as rotted decking, spaced boards or framing damage. A good contractor explains the change, shows photos, and gets your agreement in writing before continuing.
What is a redeck on a roof?
A redeck means replacing damaged roof decking or covering the existing deck with new sheathing so the new shingles sit on a solid, even surface.
Is OSB or plywood better for roof decking?
Both are widely used. Which one a roofer chooses often comes down to cost, availability and the shingle manufacturer's and building code requirements. In our practice, OSB has been the more common choice on recent redecks because of the price of plywood.
Will my insurance pay for roof decking?
It depends on your policy, the cause of the damage and what is found. This article can't say what your policy covers. Read your policy and ask your agent or insurance company.
What does Ordinance or Law coverage mean?
In general, it is a policy feature that may help with the added cost of meeting current building codes when a covered loss requires repairs. Whether you have it, and how much, is written in your policy.
Do I need a permit for a roof replacement in Oklahoma City?
Permit requirements depend on your city or county and the scope of work, so ask your roofer which permit applies and how inspections will be handled.
How can I tell if my roof has spaced decking?
Look at the underside of the roof from the attic. If you see individual boards with gaps between them, instead of solid sheets, it is likely spaced decking. A roofer can confirm this at the estimate.
Talk to a local roofer before the storm, not after
If you want a roofer to look at your roof and the attic and put the decking question into writing, Total Roof Protection OKC can walk through it with you. Call 405-415-5841 to ask about an inspection. We will explain what we see, what an estimate does and does not include, and what questions to take to your insurance agent.