Is there a reliable stud finder for locating Rafters?

[Sunnydays]

Hammer time.

I use a hammer to locate the studs. You can hear the difference, and you can feel the difference too, without gloves that is!!!!

[Designer_Mike]

I would imagine a strong magnet....I mean REAL strong magnet would work. It would be a two person job, but you should be able to mark them out fairly quickly.

Hold the magnet to the inside edge of the rafter and move some metal around on the roof. You should be able to get very close.

Although.... I'm sure it's been tried before!

I use some safety switches that will "mate up" through about 3/16" thick stainless steel but they ain't cheap either!

[vinniethePVtech]

Bosch makes a tool called the D-tect 150 that I have heard good things about. I have no personal experience with it, but our customers are always looking for a way to find rafters consistently.
Until recently it was not available in the states, but at the solar show last week in Dallas Bosch was showing the product and giving one away, and a google search yields American retailers.
It is expensive, somewhere in the $800 range, but it could pay for itself fairly quickly with time savings.
The German site for the product is here:
http://www.wallscanner.de/gb/en/index.htm

It wont pay for itself quickly because of the rarity of its use, and time for assessing during its use. Hilti makes one very similar to the bosch that is a little over a grand. If thebosch does become available it would be better to rent than to own, and tack 10% of rental price to the customer. A delicate tool of that nature is not something you want to own.

[Chris @ EcoFasten Solar]

Bosch makes a tool called the D-tect 150 that I have heard good things about. I have no personal experience with it, but our customers are always looking for a way to find rafters consistently.
Until recently it was not available in the states, but at the solar show last week in Dallas Bosch was showing the product and giving one away, and a google search yields American retailers.
It is expensive, somewhere in the $800 range, but it could pay for itself fairly quickly with time savings.
The German site for the product is here:

http://www.wallscanner.de/gb/en/index.htm

[Naptown]

On shingle roofs with asphalt shingles I just use a hammer to locate the rafters. Works every time. Cedar or tile roofs are a different story however.
There is one stud finder made for this purpose and will locate them under up to about 6" of foam etc. I have heard of this but do not own one I have been told they are expensive.

Craftsman makes one that will scan 1 1/2" deep for $20.00

[Husketeer]

Stud finders won't work. Shingles are to heavily insulated. I've tried it all. Tack 3 hours onto initial bids to compensate for the time spent in the attic. You are going to need it.

Thanks Vinnie, that confirms what I already thought. The current project is a large triangular roof where the rafters change half way up, Ive had to drill more holes than I wanted to to locate the position of the rafter changes as there is datum edge to measure from being triangular. Just trying to find a better method than having to drill holes in the roof, it makes customers nervous.

[vinniethePVtech]

Stud finders won't work. Shingles are to heavily insulated. I've tried it all. Tack 3 hours onto initial bids to compensate for the time spent in the attic. You are going to need it.

If you are popping holes in the roof I can only recommend Henrys 208R caulking tar for holes smaller than 1/4".

[Husketeer]

Hi, new to the forum but have been installing solar PV systems for the last 18 months in the UK. I have just recently moved to Canada and I have been fitting systems here for the last 5 months. The installation techniques are different here due to the plywood over rafters roofing structure with shingles as the roof covering.
In the UK you can simply remove the roof tiles to locate the rafters whereas here you need to measure the rafters from inside the attic and drill a hole next to a rafter as a point of reference on the roof.
My employer whilst he understands this technique is concerned about the roof leaking in the future due to the winter climate we have here in Canada and the hot summer causing the sealant we use to crack and eventually fail.
Sooo my long winded question(s) are, has any installers on here managed to find a stud finder that can locate the rafters through the shingles consistantly as I have found stud finders unrelaible on dry wall let alone through 3/4" plywood and shingle. If you guys have please can you recommend one, also any experience of how better to seal these roofs if you have a hole to fill.
Thanks in advance for any replies