Noise in flat roof,sounds like someone is walking on it

The house is in Los Angeles area. Roof if flat and was redone last December (only few months), but it was installed on the top of the old roof. This noise is so bad because it sounds like someone is walking on the roof! We haven’t slept in this house yet, but it sounds like this noise appears usually in the morning (when sun starts to warm up the roof) and after the sun goes down and roof cools off. We are not sure if this is something that might settle after few months or we would have to do the roof…
New roof that was installed is a APP Membrane. I’m not sure what was installed there before. Any ideas what I should be doing?

What sort of recovery board (I assume they used one) is over the original system?
It’s possible the recovery board joints are interacting when the roof heats up. Since the recovery layer is typically mechanically fastened, it could also be fasteners pulling on substrate where recovery board bridges an area of substrate deflection.

Otherwise it might be a ghost, or those pesky neighbor kids! :smiley:

I’m not sure about the recovery board as I’m not the roofer… All I know is that this noise appears when sun hits the roof and I have a feeling that this is cause mainly because the new roof was installed over the old one…
I have spoken to some engineers and they are saying it might be possible to loosen some joist on the side of the house to let the roof have more room for expansion… Instead of redoing the roof.

Maybe the possum gets up in the morning and searches for food and returns at night. I have seen this happen. In that case you do have someone walking on your roof. Don’t rule it out.lol

I doubt it as the noise is very loud and it sounds like a wood expansion not the small animal. Plus we have only 6-8 inches of height and there isn’t really enough room for them to move.

It must be pretty bad if you’d even MENTION re-doing the roof. Sorry for your situation.

Unless someone has a better explanation, (and without seeing it) I’m still of the opinion the recovery board joints are popping due to tight abutment and stress of thermal expansion, or a deflection bridge.

It may be possible to relieve the pressure in the manner you described (without seeing it). It may also be possible to screw from above the joist to draw the board edge tight.

Are you able to identify a certain area, or is it spread indeterminately?
Can you post a photo of the roof?

Yes, it is pretty bad… it feels like all of the sudden someone is walking on the roof. We have 3 bedrooms and large living room. 80% of the noise is above the living space which obviously has a large open ceiling compared to the bedrooms. Another 20% are in the master bedroom which also has a pretty big open ceiling.

If you go on the roof and walk on it, then you also get the similar noise, but walking on the roof is not as bad as this noise it. When t happens it almost sounds like it start on one end of the living room and goes all the way towards the bedrooms… like it is a wave.

How can I check if I even have board joints? Or every flat roof has one? Sorry, I’m not that technical when it comes to roofs :slight_smile:

I can certainly take pictures tomorrow and post them. Is there anything else I can check to know what are my options other than replacing the roof?

Also, is that normal that the roof is only 2 months and there is already a small hole on the edge near the gutter where the water is already made its way and is going on the roof? Does this mean the roofer did a terrible job? Or this kind of stuff happens from time to time?

Be sure to post a photo of the hole at the edge as well. Am I understanding correctly that water is already entering the roof system? If so, this is a failure.
Generally, recover boards come in either 4’x4’ or 4’x8’sheets, and are used to make a flat surface upon which to install the waterproofing membrane.
There are a number of materials used for this, such as plywood, OSB, wood fiberboard, gypsum board, etc. Usually you can see a faint outline of the board joints through the membrane, and assuming they mechanically attached the recovery boards you’ll be able to see or feel fasteners and plates where they put them through to attach. In walking the roof, if you apply foot pressure to a board joint and it pops or moves, it is not rigid enough to bridge a deflection in the substrate. This should have been screwed tightly. It could also be a problem with the decking itself, if not attached firmly to the structure.

I guess another possible source of the problem could be the entire structure shifting, and the newly-installed board being rigid does not shift along with the previously existing. I only infer this by your description of edge problems, however, and could be completely wrong.
In any case, a 2 month old roof should not have failures, in the edges or otherwise. Do you have a warranty?

I forgot the camera at home today so no pictures. Will post them tomorrow. However, I my roofer (no the one who installed a new roof) come out today and look at the roof. He showed me that all around the roof, on the edges the new roof is peeling off… as soon as you lift it without applying any preasure it comes off and you can see the water in between the old and the new roof… My roofer says that they didn’t even bother removing few inches of the old roof from the edge so they can secure the new roof properly… So it sounds like a new roof isn’t attached to the old roof as it should be. He also said that when he walked on the roof he felt that some wood was not as firm under him so he thinks that the old roof which is 20+ years has a lot of damage underneath and possibly required some joist replacement.
He rocomended installing a rigit insulation upon removal of both roof layers and then putting a new roof and then applying a special white (pain like) material that will protect the roof and will work as reflective material from the sun.

what type of system is the top layer? Could you describe it if you don’t know the proper name?

Sorry about your roof issues, it sounds like your roof has very real problems.

[quote=“Rosco”]what type of system is the top layer? Could you describe it if you don’t know the proper name?

Sorry about your roof issues, it sounds like your roof has very real problems.[/quote]

It is APP Membrane and the one below might be the same thing… my roofer said that they didn’t even bother scraping the bigger rocks from the old roof before putting a new one!

[quote=“Cerberus”]It certainly sounds as if you have some expansion/contraction movement in your roof system. I would have to know more about what is in place and what kind of roof was installed overtop the existing before I can even begin to help. All the same, I suspect you are hearing something becoming unstuck/unsecured/etc. from a substrate as the roof heats up and expands. As it cools down you will hear the same noises.

Tell me, does it seem to be “better” on days where there isn’t much temperature change and it is overcast so the sun can’t heat up the roof?

Photos, need photos! Overviews, close-ups, perimeter, etc.[/quote]

Photos will be posted today.
Yes, you are absolutely right! Noise is gone during the rainy/overcast days… We were in the house for several hours in the morning and in the evening on the rainy day and heard no noise… It is definitely related to the heat and mainly sun, because it could be warmer but no sun and roof most likely won’t make noise.
I will make pictures of the roof itself, then will lift the new layer to show the old one.

From what I gather it sounds like the original roof was a BUR- (Tar and gravel), and a Modified bitumen APP system was installed directly the BUR.
I come across that alot around here, however I have never heard of any noises of what you describe.
I must say that most of them do not last to long before they start leaking and I have seen a few that have blown off completely in high winds.

Here are the pictures. You can’t really seethe water in between the old and new roof, but there is a water there and it smells really bad!

http://www.fredmagid.com/roof/P1010127.JPG
http://www.fredmagid.com/roof/P1010128.JPG
http://www.fredmagid.com/roof/P1010130.JPG
http://www.fredmagid.com/roof/P1010131.JPG
http://www.fredmagid.com/roof/P1010132.JPG
http://www.fredmagid.com/roof/P1010133.JPG
http://www.fredmagid.com/roof/P1010134.JPG
http://www.fredmagid.com/roof/P1010135.JPG
http://www.fredmagid.com/roof/P1010136.JPG
http://www.fredmagid.com/roof/P1010137.JPG

Cerberus, removing everything and securing fixing joist and also installing Rigit insulation is my plan. However this roofer was paid almost $5000 by the company whom I’m buying this house from. So I would like to know my options and what can I do to get at least some $$ from this roofer to redo the roof. Is there some kind of special inspection which will give me a valid paper that will state that the roof job was not done properly so I can take this company to the court?

Today I received an estimate from a roofer that did one of my roofs 4 years ago for a very reasonable price, but his quote for this job seems very high. Can someone tell me if sounds reasonable?

to remove old roof7200sq ft $4,600
(he quoted 3600X2 because of 2 layers)

to install plywood & insulation $2,500
(just labor)
to install new modified roof membrane $3,500
(labor)
Material $13,600
(roofing material, plywood and Rigit insulation)
Reflective paint and labor $1,500
(labor and material)
Total labor and material =$25,700
plus city permit s
not including any rotten wood price

[quote=“MTRX”]Today I received an estimate from a roofer that did one of my roofs 4 years ago for a very reasonable price, but his quote for this job seems very high. Can someone tell me if sounds reasonable?

to remove old roof7200sq ft $4,600
(he quoted 3600X2 because of 2 layers)

to install plywood & insulation $2,500
(just labor)
to install new modified roof membrane $3,500
(labor)
Material $13,600
(roofing material, plywood and Rigit insulation)
Reflective paint and labor $1,500
(labor and material)
Total labor and material =$25,700
plus city permit s
not including any rotten wood price[/quote]

I think this is a fair price. honestly, it might be a little low. Find out more about the mod bit he will be putting down. i.e. how many layers, what kind of edge treatement he will use. Learn a bit about flat roofing and ask him all pertinent questions. You don’t want to have the same thing happen on your buck. I would consider putteing down EPDM also.