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Roof Cleaning Collegeville PA · Guest

Formula for measuring Square Footage...

Dustin Miller · Guest

You can take the base square foot and multiple that by 1.3 or 1.5 depending upon the pitch of the roof. or... you can count how many shingles go up the roof. Each shingle should be exposed approx 5". So if you have 60 shingles times 5" per shingle that gives you 300" divided by 12 gives you 25 foot then take that multiplied by the width.

Hope this helps. Someone else might have a better trick.

RoofBright of Florida · Guest

The formula's we use are length X width X1.40 for a 12x4 roof. for 12X6 roof pitch we use 1.60 and a 12X8 we use 1.80

Example 45' X 60" = 2,700 X 1.40 = 3780 sq ft of roof space.

RoofBright of Florida · Guest

Sorry I didn't explain. Meaurements are length X the width of the exterior to which to add the multiplier.

Roof Cleaning Collegeville PA · Guest

Wow. This is exactly the type of answer that I was looking for. I plan on appyling the # of shingles going up the roof trick to double check the "pitch multiplier" formula.

Thank you
Thank you
Thank you!!!!!!!!

plinscott · Guest

I don't know about everyone else but I usualy round up or down. I don't get too hung up on exact numbers of square feet. If I am off by 100, 200 or even 300 sf its not a big deal cost wise.

Roof Cleaning Collegeville PA · Guest

I'm sure that after I get the hang of it, I too, will be able to round up or down with relative accuracy. I don't see myself spending an hour just measureing a roof. However, I'll have to learn it "longhand" so-to-speak until I get the hang of it.
I estimate window cleaning by simply counting the total # of windows, multiply it by $8 then I add $$ depending on various factors. After a while, ya just get a "feel" for it..

plinscott · Guest

I draw the roof layout from a birds eye view. After that you can add the triangle shapes together that are the same (two triangles make a square is what I mean). If you have a section that is cut up just measure it out then on paper chop it up into smaller squares or rectangles. Grid paper helps keep the lines straight if you have a crooked eye like me.

Roof Cleaning Collegeville PA · Guest

The grid paper is a good idea. I like to document everything about my customers so that when I go back, I'll know exactly what's up. There's no way to remember everybody so, having a drawing and/or picture of the house(s) is quite helpful.

andy hinson · Sep 13, 2009

A formula simular to RoofBrite is what I use

cascapi · Guest

I add the main floor SF to the garage SF (it's public info on our county assessor's website, and, obviously main floor + garage + porch = roof coverage), and multiply by 1.15 to get close (most of our roofs are 4/12 or 6/12). I check google maps and bing maps (bird's eye view), to look for porches or anything else weird.

I do all that in about 5 minutes, and then when I do a drive by, I'm already confident of size, so I'm just confirming the condition of the roof.

will do mildew · Guest

You can get a laser that measures feet at homedepot for 39.99 measure length and measure width then multiply together for your total square footage. then add in exteas

leith

cascapi · Guest

Here are the multipliers for converting SF to a pitched area.

So, 1500 SF of area on a gabled roof that is 4/12 only adds about 80 SF of coverage (1500 * 1.054). But go from 4/12 to 6/12 and you add almost 200 SF of shingle coverage!

Common Roof (gables):
1/12 = 1.003
2/12 = 1.013
3/12 = 1.03
4/12 = 1.054
5/12 = 1.083
6/12 = 1.118
7/12 = 1.157
8/12 = 1.201
9/12 = 1.25
10/12 = 1.301
11/12 = 1.356
12/12 = 1.414
13/12 = 1.474
14/12 = 1.536
15/12 = 1.6
16/12 = 1.66

Hip Roof:
2/12 = 1.02083
3/12 = 1.015
4/12 = 1.0273
5/12 = 1.042
6/12 = 1.06
7/12 = 1.081
8/12 = 1.105
9/12 = 1.131
10/12 = 1.16
11/12 = 1.191
12/12 = 1.224
13/12 = 1.259
14/12 = 1.295
15/12 = 1.334
16/12 = 1.373

-- Edited by cascapi on Monday 28th of September 2009 06:00:59 PM

Roof Cleaning Collegeville PA · Guest

Dude, you're taking all of the work out of this job. smile

These are great formulas. thanks!

Satcahr · Guest

RoofBright of Florida wrote:

The formula's we use are length X width X1.40 for a 12x4 roof. for 12X6 roof pitch we use 1.60 and a 12X8 we use 1.80

Example 45' X 60" = 2,700 X 1.40 = 3780 sq ft of roof space.

Now you have me confused... is that supposed to be 60ft?
Sorry, I am a wee bit slow...

andy hinson · Oct 15, 2009

It is I'm sure. Not many 60 inch measurments in the roofs I see. Observant on your part though.

Roof Cleaning Collegeville PA · Guest

YES. That was meant to be 60 feet, not 60 inches.

One thing that I'd like to get clear though is, what is meant when we say a roof is "12x4 pitch" or whatever. Could someone verbalize this. Please correct me if I'm wrong but, what is meant by saying a roof is say... 12'x4' means that for every 12 feet that a roof goes out, it goes up 4 feet. In other words, it is a "4" pitch roof. We could easily walk on that.

Again, someone please correct me if I'm wrong.

Ohio Roof Cleaning · Guest

Yep, the roof pitch is usually calculated in inches since you would normally use a level, a square and a tape measure. Guess it doesn't matter what units you're talking about though. Could be that the roof rises 6 beers for every 12 beers it runs, for instance.

Roof Cleaning Collegeville PA · Guest

Okay, so what you saying is, that it would then be a SIX beer roof...?

KP Diamond · Guest

OMG HELP!!!!!!!!!!!!!!!!!!!!!!!!!

Is this a 60 inch roof or the biggest f*#*@#* human-being EVER????!!!!!

Either way, I need to bid the roof accurately, so please give me your most accurate quote to the penny....

Here are the details....NO water at the site, tons of landscaping, endangered species of lots of everything living in the gutters, can only be done at night during a full moon during the Vernal Equinox, must be a card-carrying member of the Roof Cleaners Union, the Environmental Protection Agency will have 3 onlookers for every One Square of shingle area.

Addendum to proposal: No SH or TSP or H2O to be used.

2nd Addendum to proposal: Flying fish and flying squirrels have been know to frequent the area during the Vernal Equinox.

PS. Although they are known to exist, Flying Pigs have NOT been noticed in the immediate vicinity, so you need not be wary of their sudden appearance nor should you include it in your bid.

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