Repairing Weather Damage

[Dragon77]

Ok here's the situation: I have a tile roof (So Cal terra-cotta style) that has begun to leak, supposedly from wind damage. I had the insurance agency roofing contractor out to assess the damage and they only isolated the one area where I know it's leaking into the interior. They allocate a flat $750 for wind/weather damage.

So I have had other contractors out (only those whose license I could verify with the state and who were listed with the BB). So far, I've dealt with 3 - only one of which had anything valid to say.

I have been up on the roof and inspected the state of it and the specific area I know is leaking.

The tiles are only board-laid, not nailed. The felt is extremely weather-beaten and curling up (due to the fact that it was stapled down, not nailed).

The contractor who pointed these issues out said that the board-laid was not good, for two reasons; 1) the tiles remain loose, thus making wid/weather damage more likely, and 2) the board itself blocks the runoff from the rain that does get under the tiles, forcing it to soak in, which encourages mold growth. He said he was certain that I am incurring interior leakage in areas that I cannot access (over the garage, etc).

He recommended removing all the tiles and the tile board strips, replacing the old 30# felt with 40#, and nailing the tiles back in place - over the entire roof.

My questions are as follows: 1) is this all valid? 2) is it too much of a job to take on myself? and 3) what kind of timeframe would this entale (single-story 1525sqft)?

My main concern would be verifying the areas and flashing around the chimney and vent pipes. I have pictures of the damages areas and the condition of the underlying felt, if necessary.

Thanks for any and all assistance! :)


--- Adam

[shinstr]

Adam,
Great Questions, and I see you have done your homework so far on the contractors...good job

Ok, roof tile....we will start from the bottom up...

First- is the substrate, I will "ass-u-me" from your post that you have the minimum code required(in your municipality), plywood or sheathing, usually 15/32" or greater. Removal of the existing tile to allow you to inspect and repair any damaged substrate that cannot be seen until the tile are removed, is always a good idea.

Second- a #30 felt underlayment, this is the minimum requirement by most code bodies. The underlayment is a very crutial component in the system as tile, by nature of their design, will allow moisture entry in blowing, driving, heavy rain events. Going to a heavier felt is a step in the right direction, however felt is felt is felt..no matter the thickness.
This is a good place to spend a little extra in upgrades, as it is your last line of defense. There are several different type of underlayments available from #30 felt to underlayments designed for tile roofing, to a self adhering Ice and Water Sheild membrane. (if you live in snow country, the latter is the best option)

Third- wood battens horizontal to the slope for attachment of the tile.
Again many choices here..Horizontal battens should have a gap or break in the batten 1/2 inch wide every 4 lineal feet to facilitate drainage of moisture.
In some cases the battens are installed on shims or counter battens run vertically,to elevate them for drainage. Any of these methods are acceptable
and for obvious reasons shims or counter battens are preferred as they have the most optimal drainage ability.

Fourth -Attachment of the tile to the battens is also dictated by local code bodies and slope or pitch of the roof. Typically 1 nail per tile in the field and two at the eaves, rakes and other perimeter edges. Over a 25% slope and all tile get 2 nails. Attachment of the tile directly to a plywood substrate is acceptable, however battens are preffered as there will be less fastener penetration of the underlayment, and tile placed directly on the deck can actually impeed more drainage than the battens would have.

Fifth - Flashings...Tile roofing depends on its flashings and underlayments to maintain it's water shedding ability. The tile themselves usually only leak if one is missing or broken, or improperly installed originally. Again this is good place to spend a little extra and pay close attention to detail. Galvanized flashings eventually will rust and and fail, coated steel will last longer and comes in many colors. Copper or lead-coated copper or tern-metal will most likely out live the structure itself.

So much for tile roofing 101...If your a real handy guy, take it a section at a time and figure in a minimum 10% loss of tile for breakage in the removal and replacement process.

Time?...by yourself? A LOT!!

You can find all the information that is considered "standard practice" at The Roof Tile Institute's website, look for a download named "tile design for moderate regions" and another "for cold regions" and get the one for your climate. These publications will tell you more than I could ever hope too.

Good Luck!