Wavy roof issue

[chris cochran]

I am looking into purchasing a mid 90's model home in arizona that has a flat roof over the garage. When I got on the roof I noticed there is a wavyness to the roofing. All the roofing seemed solid and this is where the AC unit is located. So it is my suspicion that this is happening due to impropper drainage from the AC unit. The house has been on the market for a month or so, and there is clearly leaves clogging some of the drainage gutters. I am definitely no expert on the matter, but everything else with the house seems to check out great. I am curious if anyone knows what this is, if it is major, if an inspector will not allow this to pass on inspection, and if it would be an expensive fix or not? I appreciate any help I can get on this. Also, I will be using a VA loan,which I hear can be more scrutinous if that makes any difference to mention or not... pictures are attached below.

3027530276

[William Cline]

You state the roofing is "all solid". Does that include the wavy area? Can you see the roof sheathing from the inside? Is it also wavy? Does it show water staining? Is it decayed? If not, I would say this is deflection from the load of the AC unit. It is a ponding problem. The costs will depend on the local contractors and the amount of repairs necessary.

[chris cochran]

You state the roofing is "all solid". Does that include the wavy area? Can you see the roof sheathing from the inside? Is it also wavy? Does it show water staining? Is it decayed? If not, I would say this is deflection from the load of the AC unit. It is a ponding problem. The costs will depend on the local contractors and the amount of repairs necessary.

Thanks for your response, I'm not too sure about the sheathing. Pardon my lack of knowledge on the subject. On the inside of the garage it looks as though two of the dry wall sheets will need replaced on the ceiling due to sagging along the wall and visible water damage. The rest cosmetically looking up at it from inside the garage looks undamaged. I walked "gingerly" the entire surface of the roof (including wavy areas) and it seems fine considering I way around 200lbs. Basically, I'm contimplating purchasing the home before it turns into a short sale and having to deal with the bank. This would be my first purchase and I have no problems fixing up a place. It is selling for 175k and with what seems to be just the issue with the roof and some out dated appliances along with some landscaping it could be a 225k house for the area it is in. I will need to have the roof work done first in order to pass VA inspection if I do move forward. So I am weighing the option of moving forward if it can be done for $1,500 or so before inspection or not.

[Raymond Wand]

1. Likely concealed damage
2. Deficient roof framing
3. Damaged framing/sheathing
4. Weight of water (ponding) scuppers clogged
5. Modified roof covering failing/failed.
6. Patched
7. Plumbing vent has no pitch pocked and patched.

Proceed cautiously. Budget monies for replacement/repairs.

[Garry Sorrells]

Chris,
The wave could be the result of the thickness (my guess 1/2") of the sheathing/deck material applied over a 24"OC rafter. The wave/sag is a potential problem as it will cause ponding. I also would question the type of surface material used. It looks like 100lb mineral (roll roofing). You mentioned drywall sagging and water stains. New or old really doesn't matter.

The real correction to the roof would be to replace the deck and coverage. Complete tear off. I am not familiar with your local rain amounts. If it rains only once or twice a year you may not be to concerned for the immediate future but long term replacement is the answer. I would not be surprised if there is some rotten wood there also.

Get a good roofer to quote you a price. It will be more than $1500. I know there is a lot of cheap labor in your state so be wary of who you get.

[chris cochran]

Chris,
The wave could be the result of the thickness (my guess 1/2") of the sheathing/deck material applied over a 24"OC rafter. The wave/sag is a potential problem as it will cause ponding. I also would question the type of surface material used. It looks like 100lb mineral (roll roofing). You mentioned drywall sagging and water stains. New or old really doesn't matter.

The real correction to the roof would be to replace the deck and coverage. Complete tear off. I am not familiar with your local rain amounts. If it rains only once or twice a year you may not be to concerned for the immediate future but long term replacement is the answer. I would not be surprised if there is some rotten wood there also.

Get a good roofer to quote you a price. It will be more than $1500. I know there is a lot of cheap labor in your state so be wary of who you get.

Thank you gary,
Your information was very helpful. Since we don't get a whole lot of rain here in arizona my immediate concern is passing the home inspection, especially since the flat roof (problem area) is only covering the garage as well. Long term replacement will definately be the ultimate goal, but hopefully after getting in, so I can spend the necessary money to have a good quality replacement.

[Ken Amelin]

I am looking into purchasing a mid 90's model home in arizona that has a flat roof over the garage. When I got on the roof I noticed there is a wavyness to the roofing. All the roofing seemed solid and this is where the AC unit is located. So it is my suspicion that this is happening due to impropper drainage from the AC unit. The house has been on the market for a month or so, and there is clearly leaves clogging some of the drainage gutters. I am definitely no expert on the matter, but everything else with the house seems to check out great. I am curious if anyone knows what this is, if it is major, if an inspector will not allow this to pass on inspection, and if it would be an expensive fix or not? I appreciate any help I can get on this. Also, I will be using a VA loan,which I hear can be more scrutinous if that makes any difference to mention or not... pictures are attached below.

3027530276

Chris,

Although the photos provide us with some information and we can provide some comments based on what we see, someone needs to be there to provide you a full evaluation. My advice is to hire a Home Inspector to provide you with a complete inspection and report. I would imagine you have an inspection clause in your contract and it would be in your best interest for an experienced person to evaluate the entire building. The roof is only one element of the house.

I urge you to contact an experienced Home Inspector to help you with this purchase. Home inspectors have seen thousands of homes and know what to look for. Their only interest is to identify building issues or defects that will help you better understand your purchase. Good luck.

[Ray Thornburg]

It appears to be a flat roof. Flat roofs do have a minimum slope and they must slope continuously towards the drains. If there is a low spot as your picture shows it means that there was probably a leak which weakened the plywood causing the waves. Flat roofs are difficult to patch even if there is no damage. The water vapor which is trapped between layers will form a steam pocket on hot days resulting in more leaks and damage even if it doesn't leak. Looks like the whole roof decking needs to be replaced from your picture. Best to call a qualified roofing company experienced in flat or built up roofing systems for a quote or advise.

[Larry Morrison]

Is it the roofing material only that is wavy or the plywood/OSB decking under the roofing material?

If it is just the roofing material, I'm betting with the movement it will be coming apart and leak at the seams. Already looks to have been patched and could have hidden damage to decking and or trusses/joists.

If it is the decking underneath I would say you have potentially bigger problems. My guess is that it was installed without the proper spacing and/or leaks have damaged the decking causing the decking to expand, heave and probably is coming apart.

[Bruce Ramsey]

You have posted several times "pass the inspection". Home inspections are not Pass/Fail. They are a documentation of the condition of the home on that date and time. Only the buyer decides to Pass or Fail the home.

A home inspector will evaluate the home and provide you with a written document of all the identified defects. You easily have more than $500 worth of visble repairs to the roof. A home inspection would help you to identify all the other repairs needed for this home. Particularly since you are a first time home buyer. You need to attend the entire inspection and listen to the inspector.

[Larry Morrison]

You have posted several times "pass the inspection". Home inspections are not Pass/Fail. They are a documentation of the condition of the home on that date and time. Only the buyer decides to Pass or Fail the home.

A home inspector will evaluate the home and provide you with a written document of all the identified defects. You easily have more than $500 worth of visble repairs to the roof. A home inspection would help you to identify all the other repairs needed for this home. Particularly since you are a first time home buyer. You need to attend the entire inspection and listen to the inspector.
Totally agree with Bruce! Very seldom do I do an inspection where I do not uncover condition issues that far out way the cost of the inspection. Things a buyer really needs to know about.

[Don Putnam]

Chris,

There is not enough information provided to be able to comment on the waviness but everything else about this roof looks like trouble:


required membrane base flashing is absent along the base of the parapet wall.
the use of roofing mastic to seal around the pipe penetration, scupper, and seams in the field of the membrane are a bad sign. proper flashing and seaming techniques do not involve the visible use of mastic. mastic is often used in this manner by low-skilled roofers to try and stop leaks.
the overall appearance of the roof suggests low-skilled roof application.
the heavy accumulation of tree litter indicates lack of attention and maintenance.
tree debris can quickly clog small drainage scuppers and lead to roof collapse unless adequate provisions are made for emergency overflow drainage.


You will find that Arizona has infrequent rainfall compared to other areas of the country, but it does get severe storms and the occasional 'gully washer", so it's not like having a good roof is any less important in this case.

Don Putnam
www.roofconsulting.com (http://www.roofconsulting.com)

[BridgeMan]

"Visible water damage" in the garage, combined with the shoddy work on the topside, are not a good sign. Find a good home inspector, preferably one having a roofing background, and make sure he lists every single issue he finds, in the entire house. Most VA loans require repairs to all deficiencies found before the loan will be approved.

[Jerry Peck]

I am looking into purchasing a mid 90's model home in arizona that has a flat roof over the garage.

"mid 90's"

As in 1890s?

That sure looks like it is a lot older than a 1990s structure.

Is that vent stack cast iron? It does not look black like ABS and it is not white like PVC. I have not reviewed the other posts (except for looking for other comments on age and I didn't see any), but there are several issues on that roof.