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Your Questions & Answers

Q: Why does my roof only leak during windy, heavy rains?

A: A flat roof gets very wet no matter how much the wind blows. If the leak is wind related, it is usually on a vertical surface like a chimney, vent or party wall that doesn’t get as wet when the rain falls straight down.


Q: Why do I have a crusty, powdery residue that forms on the inside of exterior walls and beneath my windows? No matter how much I scrape and apply stain blocker, it returns.

A: The residue is a type of calcium salt that leaches into your house from the mortar and plaster that make up the original outer walls of most older row homes. It is a natural process called efflorescence and it is caused by the dry, low humidity of the inside of the house that "wicks" or draws the moisture (water) from the outside of the wall to the inside. The water picks up soluble calcium from the old plaster and bricks and deposits it on the inner wall when the water evaporates inside the house. It usually will not go away for long unless a "vapor barrier" is installed to keep the water on the outside and even then it will likely return. Seldom do plaster and brick walls grow mold.


Q: Why does my recently renovated row home have black mold spots on some walls and ceilings?

A: A combination of things make mold. The spores that cause it are everywhere. They just need food and water to thrive and form colonies (ick). Usually that involves an unventilated, insulated area that is below an outside surface (wall or roof) that has water or moisture present. Sheet rock, saw dust, insulation paper and other organics provide the food and growing medium for the mold to flourish. The water gets in from a small, leaky opening on a roof, window or wall which wets first the sheathing, then the insulation and lastly, the back of the sheet rock. Mold shows quickly and should be dealt with by adding ventilation to the closed cavity, proper waterproofing of the roof or wall and removal of the moldy insulation or sheet rock. Often, mold will grow in areas where bathroom fans and other vents are not ducted to the outside and when run, will throw moist air from bathrooms and kitchens into blind spaces between studs and rafters. Mold will not readily grow on plaster as it is not organic.


Q: Why do Philly houses have so many chimneys, and why do they all leak?

A: When the Victorian row house you now live in was new it had zone heating…sort of. There was a fireplace chimney with its own brick flue on each floor or in each room and another one was in the kitchen for the "bucket a day" coal fired cooking stove. That can leave up to 10 chimney flues on a big Delancy St. brownstone, but usually 2-4 on most homes, made with old soft bricks and no linings. They burned coal for almost a century, were instantly abandoned when gas and oil came out and carried TV antennas for a few more generations. Most of them are still untouched and in need of proper closing and sealing.


Q: Everyone on our block has a tree in front of their house, except us. We have all of their leaves. Is there anything we can do that doesn’t involve chainsaws?

A: Leaves on the roof will not block drains if they can't get into it. A long tube made from 1/2 inch wire mesh, shaped to lay over the drain opening and onto the roof will keep the drain opening open and leaves and other vegetation from plugging the drain outlet.


Q: My roof is about 10 years old and doesn't leak. Should I replace it before my contractor installs a deck on top of it?

A: A roof needs to last at least one day longer than the deck on top of it. The kind of roof that just doesn't leak may not be durable and waterproof enough for a deck installation. Access doors, safety rails, weight loads and how it is installed are very important considerations. Rooftop decks are the least used and most costly addition on any city house. They almost always leak. Think long and hard before you install one. They are heavy and your roof was probably not designed for a deck. The access doors leak, the drain gets blocked with your dead potted plants and the unsecured furniture blows off the roof in thunderstorms. Also, the charcoal grill has been known to fall over and catch the place on fire during windy barbecues. (a true incident). If you are determined to have a deck, get a professionally installed, overbuilt, very tight roof first and make sure there is easy access to the drain area, just in case.


Q: My next door neighbor has water leaking in his front bedroom. We share a common drain at the party wall, but have separate roofs. My roof is pretty old and has never leaked. His leak began after he had a new rubber roof installed. His roofer said it was my fault. Is this possible?

A: Common drains begat common problems. Many homes built in the late 1800's had small top roofs and one common drain was more than enough for the 2 small attached surfaces. Unfortunately, adjacent roofs usually don't get replaced at the same time, so if the house's drain with the new roof is relatively "downhill" from the other, the older uphill roof can leak into its attached downhill neighbor and never be seen from the surface. Water will travel to the lowest point beneath the new and old layers regardless of where the actual party wall is.


Q: Why is there so much difference in pricing for the same roof?

A: Many reasons including proper licensing, roofing insurance and workers compensation, or the lack of it even does the roofer pay taxes! The degree of difficulty in the installation of the roof including height above the ground, debris present, accessory repairs chimneys, attached walls, re-sloping the surface, removal of debris and even, the warranty. All of which add to the cost of the job.


Q: My roof only leaks when it snows or when there is ice hanging off the drain. What can be done to prevent this?

A: Your drain is experiencing an ice dam which occurs when melted water from the roof flows and re-freezes in the drain box and downspout. The resulting expansion of the frozen water opens the sealants at the edge of the roof and a leak occurs. Lower freezing temperatures at night stop the leak and it starts over the next morning.


Q: When there is a heavy rain small pea sized pebbles wash out into my yard from the roof drain pipe. The roof is well over 20 years old and has never leaked and, I am told, is covered with these pebbles. Should I call someone to remove them and coat the roof?

A: Never! The roof you have is either a pitch or hot asphalt roof with a slag surfacing. Slag is a byproduct of the steel process and was used to cover all the old, original hot roofs. It is impregnated into the surface to keep the pitch or dead level asphalt in place and not run into the drain. We call these old roofs "immortals" because they seem to last forever. The slag is removed only to replace the roof surface as the material below is very delicate after so many years in the sun. When the old slag roofs start to leak they are usually unfixable and in need of replacement.


Q: How often should my roof be inspected or serviced?

A: If there are trees overhanging your roof that can cause a drain to be blocked, every year, around New Years, to remove debris and to possibly prepare the roof for winter. Otherwise, every 3 years is sufficient.


Q: Which aluminum coating is better, fibered and non fibered?

A: We usually recommend a non-fibered coating be used on roofs that are in good condition and need minimal maintenance. Their application will extend the life of a good roof. The reflective surface will cool the roof and act as a UV barrier to protect the roofing membrane from drying out, cracking and breaking down in the sunlight. Fibered coatings are used more during repairs of damaged or older roofs, as an additional layer of waterproofing. They are thicker and will dry to a more coarse and dull finish than non fibered coatings.


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