Home Pro Roofing and Solar installs flat and low-slope roof replacements for homes and small commercial buildings across Santa Clara and San Mateo counties. A flat roof is not really flat, and it does not work like a shingle roof. It needs a sealed, seamless system built to hold up to sun, standing water, and foot traffic. We install GAF EverGuard TPO, a proven single-ply system, and back it with a 20 year warranty.
We serve Sunnyvale, Mountain View, Los Altos, Los Altos Hills, Saratoga, Palo Alto, Santa Clara, Redwood City, Cupertino, San Jose, San Carlos, San Mateo, and Foster City.
What a Flat Roof Is and Why It Needs Its Own System
A flat roof has a very low slope, often too low for shingles to shed water fast enough. Water sits longer and finds any weak spot. Because of that, a flat roof uses a membrane, a large sheet that seals the whole roof as one surface, instead of hundreds of overlapping shingles.
Get the membrane and the seams right and a flat roof lasts for decades. Get them wrong and it leaks early. That is why the system and the installer matter more here than on almost any other roof.
Our Go-To Flat Roof System: GAF EverGuard TPO
For most homes and small commercial roofs, we install GAF EverGuard TPO, mechanically attached. TPO stands for thermoplastic polyolefin. It is a single-ply plastic membrane that has become the most common flat roof material in the country.
Here is what that means for you:
White and reflective. The bright white surface bounces sunlight instead of soaking it up. That keeps the space below cooler and can lower cooling bills in the summer.
Heat-welded seams. We weld the seams with hot air, so the sheets fuse into one solid surface. Welded seams are stronger than glued or taped seams and are far less likely to open up over time.
Mechanically attached. We fasten the membrane down to the deck for a strong, wind-resistant hold. This method installs cleanly and works well on the roofs we see most often.
GAF Certified install. We are a GAF Certified contractor, so your roof is installed to GAF's standards and backed by our 20 year warranty.
TPO also resists UV, mold, and many chemicals, and it stays flexible through hot and cold seasons. That mix of strength, energy savings, and value is why it is our first choice.
Flat Roof Replacement Cost
Most flat roof replacements we do run from $950 to $1,500 per square. A square is 100 square feet of roof. [Russ, confirm this is per square. If the range is per project or per square foot, tell me and I'll reword.]
A few things move the price up or down:
Roof size and shape. More area and more corners, walls, and pipes to seal around mean more labor.
Tear-off. Removing old layers costs more than going over a clean deck, and some roofs hide two or three old layers.
Insulation and tapered design. Adding slope and insulation raises the price but often pays back in drainage and energy savings.
Deck repairs. If we find rotted or soft wood under the old roof, that gets fixed before the new roof goes on.
Access. A roof that is hard to reach takes more time and setup.
We give you a firm, written price after we see the roof, so there are no surprises.
TPO Compared to Other Flat Roof Materials
TPO is our go-to, but it is not the only flat roof material out there. Here is an honest look at how the main options stack up.
| System | What it is | Typical lifespan | Best for | Trade-offs |
|---|---|---|---|---|
| GAF EverGuard TPO (our pick) | White single-ply membrane with heat-welded seams | 20 to 30 years | Homes and small commercial buildings | Strong welded seams, reflects heat, great value |
| EPDM (rubber) | Black rubber membrane with glued or taped seams | 20 to 25 years | Simple low-slope roofs on a budget | Black color absorbs heat, glued seams can weaken over time |
| PVC | White single-ply membrane with heat-welded seams | 20 to 30 years | Roofs near grease or chemicals, like restaurants | Costs more than TPO |
| Modified Bitumen | Asphalt sheets applied in layers, torch or cold applied | 15 to 20 years | Small flat roofs and decks | Heavier, and the torch method carries fire risk |
| Built-Up Roof (BUR) | Layers of asphalt and gravel, the old "tar and gravel" roof | 15 to 30 years | Older flat roofs, including many original Eichlers | Heavy and messy to install, being replaced by single-ply systems |
For most homes in our area, TPO gives you the best mix of long life, energy savings, and price. If your roof has a special need, like heavy grease from a kitchen exhaust, we will tell you when PVC is the smarter call.
Tapered Design and Added Insulation
A flat roof that holds water is a flat roof that fails early. Pools of standing water, called ponding, add weight, grow algae, and slowly break down any roof. The fix is slope, and on a dead-flat deck you have to build that slope in.
We do that with tapered insulation. These are foam boards cut at a slight angle. We lay them out to guide water toward the drains, scuppers, or gutters instead of letting it sit in the low spots.
While the roof is open is also the best time to add insulation. We can install rigid ISO board, short for polyisocyanurate, under the new membrane. Adding 1 to 3 inches gives you roughly R-6 of insulation value per inch, so the space below stays warmer in winter and cooler in summer. For older homes with thin roof insulation, this is one of the biggest comfort upgrades you can make, and you only pay the labor once because the roof is already off.
Tapered design and added ISO do three things for you:
Move water off the roof so it drains the way it should.
Add real insulation on top of the deck, which cuts heating and cooling costs.
Protect your warranty, since standing water can shorten the life of any membrane.
We map out the low spots and plan the insulation before we start, so your new roof drains right and performs better from day one.
Already Have Solar on Your Flat Roof? We Handle That Too
If your flat roof already has solar panels, you do not have to call a separate company to move them. We remove your panels, replace the roof, and put the panels back on, all as one job. This is work we do all the time, and keeping it under one roof means one crew, one schedule, and one company responsible for the whole project.
Here is how we handle a roof replacement with existing solar:
Test the system first. Before we touch anything, we check that your solar system is working and record how it is performing. That gives us a baseline to compare against at the end.
Remove the panels and racking. We carefully take off the panels and the mounting hardware and store them safely on site.
Replace the roof. With the roof clear, we install your new GAF EverGuard TPO system, plus any tapered design or added ISO insulation.
Reinstall the panels. We put the panels and racking back on the new roof, sealed and secured so the new membrane stays watertight.
Clean the panels. While they are off and easy to reach, we clean the panels so they produce at their best once they are back up.
Test the system again. We power the system back up and confirm it is running the same as, or better than, your starting baseline.
Doing the roof while the panels are off is the smart time to replace an aging roof. You avoid paying twice to move the panels later, and you get a fresh roof and a clean, tested system in one project.
Flat Roofs for Eichler and Mid-Century Modern Homes
Our area is full of Eichler homes, the classic mid-century modern houses built by Joseph Eichler across Palo Alto, Sunnyvale, Mountain View, San Mateo, and Redwood City. They are known for their flat and low-slope roofs, open beams, and walls of glass. Many still have their original tar and gravel roofs, which are now at or past the end of their life.
We replace Eichler flat roofs with GAF EverGuard TPO. It gives these homes a clean, modern, low-profile look while sealing the roof far better than the old built-up system. We take care around the exposed beams and tongue-and-groove decking that make an Eichler special, so the finished roof protects the home without changing its style.
Eichler's are also famous for running hot in summer and cold in winter, partly because the roofs were built with very little insulation. A re-roof is the perfect time to fix that. Adding 1 to 3 inches of ISO board under the new membrane makes the whole home more comfortable and easier to heat and cool. If you are thinking about solar, a fresh flat roof is also a great base for panels.
Areas We Serve for Flat Roof Replacement
We install flat roofs across Santa Clara and San Mateo counties. Find your city:
Sunnyvale, Mountain View, Los Altos, Los Altos Hills, Saratoga, Palo Alto, Santa Clara, Redwood City, Cupertino, San Jose, San Carlos, San Mateo, and Foster City.
Related Services
Need something else? We also handle:
- Roofing (shingle and pitched roof replacement)
- Standing Seam Metal Roofing
- Solar (a flat TPO roof is a great base for solar, and we can install or coordinate panels once your new roof is on)
- Solar Backup Storage
- Solar Panel Removal and Reinstall
- EV Chargers
Not sure how to pick a contractor? Read our guide on how to compare roofing and solar quotes.
Flat Roof Replacement FAQs
How much does it cost to replace a flat roof?
Most flat roof replacements run from $950 to $1,500 per square, which is 100 square feet. Your final price depends on the roof size, how many old layers need to come off, any deck repairs, and whether you add tapered insulation. We give you a firm written price after we inspect the roof.
How long does a flat roof last?
A TPO flat roof installed correctly lasts about 20 to 30 years. Regular inspections and keeping the drains clear help it reach the high end of that range.
What is the best material for a flat roof?
For most homes and small commercial buildings, TPO is the best mix of long life, energy savings, and price. PVC is a better fit near heavy grease or chemicals, and EPDM rubber is a budget option, but TPO is our go-to for a reason.
Is TPO better than EPDM?
In most cases, yes. TPO has heat-welded seams that are stronger than EPDM's glued seams, and its white surface reflects heat instead of absorbing it like black rubber. EPDM can cost a little less up front.
Can you put a flat roof on a house?
Yes. Many homes have flat or low-slope sections, like over an addition, a porch, or a modern-style home. We install TPO on these the same way we do on commercial roofs.
How long does it take to replace a flat roof?
Most home flat roofs take three to five days, depending on the size and any repairs we find. We give you a clear timeline before we start.
Why does my flat roof hold water?
Standing water, called ponding, means the roof has low spots and not enough slope to drain. We can fix this with tapered insulation that builds slope into the roof and guides water to the drains.
Do flat roofs leak more than pitched roofs?
A flat roof is not more likely to leak when it is built right with a welded membrane and proper drainage. Leaks usually come from bad seams, poor drainage, or an aging roof, all of which a quality install prevents.
Can you walk on a TPO roof?
Yes, you can walk on a TPO roof for cleaning, inspections, or service. We can add walkway pads in high-traffic spots to protect the membrane.
Does a white roof really save energy?
Yes. A white TPO roof reflects sunlight instead of soaking up heat, so the space below stays cooler and your air conditioner works less in the summer.
Can you put solar on a flat roof?
Yes. A flat TPO roof is a strong base for solar, and we can mount panels without punching holes that risk leaks. If you are planning solar, it is smart to replace an old flat roof first.
Do I need a permit to replace a flat roof in California?
Yes, a roof replacement needs a permit. We handle the permit process for you as part of the job.
How do I know if my flat roof needs to be replaced?
Common signs are leaks or water stains inside, cracks or bubbles in the membrane, pooling water that never drains, and a roof that is 20 or more years old. We can inspect it and tell you if a repair will do or if it is time for a full replacement.
Can a flat roof be repaired instead of replaced?
Sometimes. A small, fresh leak on a newer roof can often be repaired. An old roof with many patches, wide ponding, or failing seams is usually cheaper to replace than to keep fixing.
What is tapered insulation?
Tapered insulation is foam board cut at a slight angle. We lay it under the membrane to build slope into a flat roof, which pushes water toward the drains and adds insulation at the same time.
Is TPO a good choice for California weather?
Yes. TPO handles strong sun and UV well, and its reflective surface is a real plus in our warm, sunny climate. It stays flexible through cool nights and hot days.
Can you replace my flat roof if I already have solar panels?
Yes. We remove your existing panels, replace the roof, and reinstall the panels as one complete job. You do not need to hire a separate solar company.
What is your process for a roof replacement with existing solar panels?
We test your system first to set a baseline, remove the panels and racking, install your new roof, reinstall the panels, clean them while they are off, and then test the system again to confirm it runs the same or better.
Do you clean my solar panels during a roof replacement?
Yes. While the panels are off the roof and easy to reach, we clean them so they produce at their best once they are back in place.
Will removing and reinstalling my panels affect how they work?
No. We test your system before we start and again after we reinstall, so you can see it is running the same or better. Careful removal and resealing keep your panels and your new roof watertight.
What kind of roof does an Eichler home have?
Most Eichler homes have a flat or low-slope roof, originally built as tar and gravel. Many are now aging out and getting replaced with modern single-ply systems like TPO.
Can you replace an Eichler roof with TPO?
Yes. TPO is a great fit for Eichler homes. It seals better than the old tar and gravel roof, keeps the low, clean mid-century look, and reflects heat to help with comfort. We take care around the exposed beams and wood decking.
Why do Eichler homes get so hot?
A big reason is thin roof insulation. When we replace the roof, we can add rigid ISO board on top of the deck to boost insulation, which helps keep the home cooler in summer and warmer in winter.
Can you add insulation when replacing a flat roof?
Yes. While the roof is open, we can add rigid ISO board, usually 1 to 3 inches, under the new membrane. This is the cheapest time to add insulation because the roof is already off, and it lowers your heating and cooling bills.
What is ISO insulation?
ISO is short for polyisocyanurate, a rigid foam board that goes under the roof membrane. It adds about R-6 of insulation value per inch. We often add 1 to 3 inches during a flat roof replacement to make the home more comfortable and energy efficient.
Does adding roof insulation lower my energy bills?
Yes. Adding ISO board under a new flat roof reduces how much heat moves in and out through the roof, so your heater and air conditioner run less. It pairs well with a reflective white TPO surface.