Greater Lansing
Low-slope roof repair
A pitched roof sheds water and a low-slope roof contains it, and almost everything confusing about a flat roof follows from that. Here is where they actually fail, why the leak appears nowhere near the fault, and why standing water is a weight problem before it is a leak.
What is actually wrong
A pitched roof sheds water and a low-slope roof contains it, and almost everything that is confusing about a flat roof follows from that one difference. Shingles overlap, so water is moving off them within seconds and a small fault produces a drip. A membrane roof is a single continuous surface holding water that has nowhere urgent to go, so a small fault produces nothing at all for a year and then a ceiling. “Low slope” has a definition rather than being a feeling: under about two inches of fall per foot, which is the point below which shingles are no longer permitted and a membrane is what the roof has to be.
They almost never fail in the middle. The field of an EPDM sheet is an inert piece of rubber and it long outlives everything attached to it; what fails is every place the membrane stops or is interrupted — seams, laps, terminations at a parapet or wall, pipe boots, curbs round a unit, and drains. The invoiced repair behind this page is a good example of the pattern rather than an exception: a hundred and ten linear feet of failed EPDM seam on a commercial unit, plus the drains cleared, for two thousand and fifty dollars. Nobody had to touch the field of the roof.
Standing water is the one thing on a flat roof worth treating as urgent, and the reason is weight rather than leaking. Water weighs about five and a quarter pounds per square foot for every inch of depth. An inch of water across a modest twenty-by-thirty-foot roof is a little over three thousand pounds that the building was not necessarily designed to hold, it does not drain itself, and it gets heavier every time it rains. A blocked drain on a flat roof is therefore a structural question and not a housekeeping one, which is why clearing drains is the first thing done and why a roof that is standing water for structural reasons gets an engineer rather than a patch.
Two membranes account for the work actually done here, and they are not interchangeable. EPDM is the black rubber sheet, repaired by cleaning back to sound material and bonding a new cover strip over the seam. Modified bitumen is the sheet product that comes self-adhered or torch-applied, and the failed areas get cut out and patched in kind — the records here are self-adhered, and torch work is not offered at all for reasons set out in the boundaries. Patching one of these in the other one’s material is the most common way a repair fails, because the patch holds and its edge does not.
A word on what the records actually are, because it matters for judging this page. The invoiced low-slope work here is commercial and light-commercial — a retail unit and a realty company’s buildings — not houses. Flat porch, addition and dormer roofs on a house are in scope and are the same work on a smaller scale, but the track record is commercial and this page is not going to imply otherwise. And on any building from before about 1990, built-up roofing felts and mastics are treated as asbestos-containing until somebody has sampled them.
Where this stops
When it is not a handyman job
This is at the top of the page rather than the bottom because getting it wrong costs you a wasted visit. Insured, and no contractor license is claimed or implied — the Michigan residential builder license is not held.
- Shingles and steep-slope coverings are not taken on at all — that is a roofer’s trade. Nothing on this page is an offer to work on a pitched roof covering, and you are told on the phone rather than after a visit.
- No stripping and re-covering a whole building. What is offered is repair, and re-covering a defined section where fall has to be rebuilt. A building that needs its covering renewed end to end needs a roofing contractor and a warranty this company cannot issue.
- No torch-applied work, ever. Self-adhered and cold-applied only. Open-flame roofing is a leading cause of construction fires, it needs a hot-work permit and a fire watch, and the answer here is simply no rather than a precaution.
- No structural work to the deck or the framing, and no judgment offered on whether a roof can safely carry the water standing on it. That is a structural engineer’s call, it gets referred, and the referral is not treated as a lost sale.
- Built-up roofing on anything from before about 1990 is treated as asbestos-containing until sampled. It is not cut, scraped, ground or disturbed, and asbestos work is excluded here.
- No roof warranty is issued. Sealing a seam is a repair, it is not a roof, and it does not carry a roof warranty — this company’s own quote wording.
- If the existing membrane is still inside a manufacturer’s system warranty, a repair by anyone who is not a certified installer for that system can void it. You get told that before the work, not after, and sometimes the right advice is to call the original installer instead.
The work itself
What actually gets done
Find the leak before anything is opened up — from inside and outside both, because on a low-slope roof the place water appears and the place it enters are frequently nowhere near each other.
Repair failed EPDM seams and laps: clean back to sound membrane, prime, and bond a new cover strip over the full length. The invoiced example was a hundred and ten linear feet.
Cut out and patch failed areas of self-adhered modified bitumen in matching material.
Repair flashings, terminations, termination bars, pipe boots, curbs and parapet junctions — the places these roofs actually fail.
Clear and re-bed roof drains and strainers, and tie roof drains into downspouts, which is separately invoiced work here.
Build fall into a dead-flat area where water is standing — tapered sleepers, new deck, and a re-cover of that defined section rather than the building.
Repair a flat porch, addition or dormer roof on a house, which is the same work at domestic scale.
Tell you when what you have is beyond repair, with the reasoning, rather than selling a patch onto a roof that needs a decision.
This work sits inside General Repairs, which carries the invoiced price bands for the trade with the sample size printed beside every figure.
What it costs
There is no price list for this, and here is what actually decides the number.
The same three words describe a twenty-minute job and a two-day one. Rather than publish a figure that is wrong for one of them, here is what moves it — so you can work out roughly which end of it you are at before anybody comes out.
Access, which on a commercial roof is routinely the largest single line. A hatch and a fixed ladder is one number; a parapet with no safe access, or anything needing a lift, is another.
Whether the deck and insulation underneath are still dry. A failed seam over a sound deck is a repair; wet insulation and a soft deck is a different job and there is no way to know which you have until a test cut is made.
How much membrane has to be lifted to find the actual water path, which on a roof that has been leaking for a while is more than anybody wants it to be.
Membrane type and whether compatible material is available. EPDM, TPO and bitumen need their own systems, and matching an unlabeled twenty-year-old membrane sometimes means a test patch first.
Whether fall has to be built rather than drainage merely restored, which brings in sleepers, decking and a re-cover of that section.
The number of penetrations. A plain rectangle of roof and the same area with eight pipes, two curbs and a condenser on it are not the same job.
How to get a real number
Somebody comes out, looks at it properly, and you get a fixed price in writing with the work set out line by line and the exclusions written down as plainly as the inclusions. Coming out to do that is not charged for, and neither is working out what is wrong. If something is found once a wall or a floor is open, it is priced as a written change order and you decide before the work carries on rather than after it is billed. Materials are supplied at cost with the receipt attached, first-time customers get 10% off labor, and labor carries a one-year craftsmanship warranty.
If this is happening right now
What to do in the next five minutes, and what happens when you ring.
Before anybody arrives
- Photograph the inside of the leak and put the date in the frame. On a low-slope roof the inside evidence is often the only usable record of how fast it is getting worse.
- Do not walk on it. A wet membrane is genuinely slippery, a snow-covered flat roof hides everything including the edge, and a roof with water standing on it may already be carrying more than it should.
- Note whether the leak starts with the rain or lags behind it. Immediate suggests an open path at a seam or a penetration; a lag of hours or days suggests water being held somewhere and tracking, which changes where anybody looks.
- If you can see the drains safely from a window or a hatch, check whether something is sitting on one. A ball, a bag or a season of leaves over a drain is the most common cause of standing water and the cheapest thing on this list.
- If this is a commercial tenancy, find out now whether the roof is the landlord’s or yours. It is in the lease, it takes ten minutes, and it saves two weeks of the wrong person getting quotes.
Call the business line
(517) 505-7135Answered Monday to Friday, 08:00 to 18:00. There is no out-of-hours line and this page is not going to invent one — outside those hours, leave a message with the address and what is happening, and it is picked up in the morning.
On the call you get asked what is happening, what else in the building is affected, and whether it is still getting worse. That is how it gets decided whether this is our job at all — and if it is not, you get told that on the phone rather than after somebody has driven out.
- No trip charge
- No call-out fee or minimum
- No diagnostic fee
- No charge for a return visit
True across all 84 written quotes this company has issued. Most contractors in this market charge to turn up.
Or send the detailsWhen the right answer is not this company
- You can smell gas
- Leave the building and call the utility from outside. Not us, and not later.
- Water you cannot stop
- Your main shut-off first, then a licensed plumber. Every minute of this one costs money.
- Sewage backing up, or several fixtures at once
- A licensed plumber with a camera. That is the shared line, not a fixture, and a cable down one sink will not touch it.
- Sparking, scorching or a burning smell at an outlet or a panel
- Breaker off, and a licensed electrician. Electrical work here is repair and like-for-like replacement, and this is neither.
- No heat, or heating and cooling equipment that has failed
- A licensed mechanical contractor. That trade is not offered here at all, and knowing that in one phone call is worth more than a visit.
Questions people actually ask
What counts as a low-slope roof?
Anything under roughly two inches of rise per foot of run — that is the threshold below which asphalt shingles are no longer permitted and the roof has to be a membrane system instead. In practice it means anything that looks flat: a commercial roof, a flat porch or addition, a garage roof, a dormer top. It does not have to be literally level, and in fact a well-built one never is, because it needs enough fall to get water to a drain.
Do you do shingle roofs?
No. Shingles and steep-slope coverings are a roofer’s trade and are not taken on here, and you get told that on the phone. What is done is repair to flat and low-slope membrane roofs — EPDM seams, modified bitumen patching, flashings, penetrations and drains — plus all of the roofline, meaning fascia, soffit, trim, flashing, gutters and downspouts. If a shingle roof is the problem, that is a roofer first; the roofline and interior work can follow it.
My flat roof only leaks sometimes, not every time it rains. Why?
That is the normal behavior of a low-slope roof and it is the reason these leaks go unfound for so long. Water that gets through a seam does not fall straight into the room — it travels between the membrane and the deck, or through the insulation, until it reaches a joint, a fastener or a light fitting and comes through there. So whether you see anything depends on how much rain fell, from which direction, and whether the water reached the exit point before it stopped. A leak that lags a day behind the weather is holding water somewhere, and where it is holding it matters more than where it is dripping.
There is water standing on my flat roof. How urgent is that?
Urgent, and for the weight rather than the leak. Water runs about five and a quarter pounds per square foot per inch of depth, so an inch across a twenty-by-thirty-foot roof is over three thousand pounds sitting on the building, and it does not go anywhere by itself. Standing water also finds every weakness it is in contact with and it accelerates the aging of the membrane under it. The first question is always whether a drain is blocked, because that is cheap and common. If the drains are clear and it still ponds, the roof has lost its fall or the deck has deflected, and that is a structural engineer’s question — which gets referred rather than patched over.
Can an EPDM roof be patched, or does the whole thing have to come off?
Patched, in most cases, and the reason is that the field of an EPDM sheet is an inert piece of rubber that long outlives the details attached to it. What fails is the seams, laps, terminations and penetrations, so a repair means cleaning back to sound membrane and bonding a new cover strip over the failure — the invoiced job behind this page was a hundred and ten linear feet of seam on a commercial unit and the field of the roof was never touched. Where it genuinely has reached the end is when the insulation underneath is saturated or the deck has gone soft, because then a watertight patch sits on top of a problem it cannot reach, and you get told that rather than sold the patch.
Will a repair void my roof warranty?
It can, and it is worth checking before anybody starts. Commercial single-ply roofs are frequently installed under a manufacturer’s system warranty that requires work to be done by one of their certified installers, and a repair by anybody else can void the remaining cover. This company is not a certified installer for those systems and does not pretend to be. So if your roof is still inside a system warranty, the right advice is often to call the original installer and that is what you will be told — and no warranty is issued on a repair done here either, because sealing a seam is a repair and not a roof.
Do you work on houses or only commercial buildings?
Both, with one honest caveat about the record. Flat porch, addition, dormer and garage roofs on houses are in scope and are the same work at a smaller scale. But the invoiced low-slope work in this company’s records is commercial and light-commercial — a retail unit and a realty company’s buildings — so when this page says the work has been done and paid for, that is the work it is talking about, and it would be overstating things to present a domestic track record that does not exist yet.
Can you torch on a bitumen patch?
No, and it is not a scheduling problem or something that can be arranged for the right price. Open-flame roofing is one of the leading causes of fires on construction and repair jobs, it requires a hot-work permit and a fire watch kept after the crew has left, and the risk is carried by your building rather than by whoever is holding the torch. Modified bitumen is available in self-adhered form, that is what has been used on the jobs here, and it does the same job without putting a flame on a roof deck with twenty years of dry felt under it.
Book a low-slope roof assessment
Photograph the inside of the leak with the date in the frame, and tell us whether it starts with the rain or lags a day behind it — that one detail changes where anybody looks. Do not go up to take pictures. Somebody then gets on the roof safely, finds the water path rather than the stain, and puts a fixed price in writing. Coming out is free, and there is no trip charge.