Measuring A Roof

Do you know how it’s done?

Measuring a roof from the ground can be a much safer way to get the information you need to do a roof. This week I was asked to teach a new solar estimator how to measure a roof from the ground. The basic idea of measuring a roof from the ground may sound ridiculous but it can be done, and done very accurately. I think everyone should measure at least the perimeters of the roof from the ground because the risk of a fall walking along the eaves of the roof can be avoided. If you are a professional and you are up and down ladders, crawling around steep, wet, damp and slippery roofs year in and year out, the odds are against you. These tips can reduce the risk of a fall. This web page is to show how the whole roof can be measured from the ground and a order for materials be placed.

So, What tools do I need to measure a roof?

1, Tape Measure. a 25 foot or longer works good. I use a laser for speed and it is very accurate. There a measuring wheels that work well also.

2, Graph Paper, some basic graph paper will help keep straight lines and scale your roof drawing. I use a two-foot scale drawing and most sizes homes will fit on a 8.5 x 11 sheet of paper.

3, Calculator, is a important tool since it will help you with complex math with less or no errors.

4, Pitch Gage, will be needed to find the pitch of a roof. There are pitch gage Apps for smart phone free to download.
Familiarize your self with the names of the parts of a roof, like the Gable, Hip, Valley, Eave and Ridge. Take a minute before you measure and Google your roof then highlight these parts of the roof like seen here to the left. It will help with your drawing later. Start from the left corner and start taking measurement from the eave to eaves all around the home. Using the graph sheet you should end up right where you started. If you don’t, then you made an error some where.

Once the site drawing is done look at the drawing and in a red marker draw out squares like seen in this drawing. {drawing has been cropped}

A, Is { 48′ x 24′ } B, { 16′ x 24′ } C, { 12′ x 24′ } and D, { 6′ x6′ } Do you see the squares? Add these four totals and you have the foot-print of the roof which is 1860 sq. ft. Now we need to add the pitch factor which is the rise of the roof. Most homes have about a 4:12 pitch or 18.5 degrees. This is as low a pitch as you want when installing asphalt shingles. This roof we are measuring today is a 6:12 pitch or 26.5 degrees. The pitch factor I use for this is 1.12. This factor should be times the house foot print, 1860 sq. feet and your roof size equals 2084 or 20.84 sqs. Lets call it 21 sqs. Determine the waste factor and you have the total roofing sqs. you need to complete this roof.

Now to determine the length of the valleys and hips needs to be calculated using the hip factor of 1.50 for a 6:12 pitch. So here in the front right side is a hip roof and the width being 24 feet. x 1.50= 36 feet, divided by 2 for each side which equals 18 feet for the hip length. The valleys are the same formula as the hips. For this short valley on the right being 6 foot equals 6 x 1.50 = 9 ft.
The eave should be looked at by a ladder to see how many layers of shingles there are on the roof. With a good roof flashing count, you can place a materials order to the supply house. Here are the pitch factors rounded up for calculating the sqs. of a roof.

Degrees converted to roof pitch

9.5° = 2:12,  14° = 3:12,  18.5° = 4:12,  22.5° = 5:12,

26.5° = 6:12,  30° = 7:12,   33.5° = 8:12,   37° = 9:12,

40° = 10:12,    42.5° = 11:12,   45° = 12:12

When To Replace A Roof

No matter how little you want to deal with them, roofing issues sometimes appear. There is never a right moment for a roofing problem to arise, although it is best to tackle them on a clear, sunny day and definitely instead of during winter. Unfortunately, you cannot always predict when your roof is going to get damaged or how. That is why you should make it a habit to take a regular look at your roof to prevent any problems. Sometimes it can be very hard to detect a problem, which is why a thorough inspection by a professional roofing contractor is required to get to the bottom of anything questionable. Unless of course, you are fully acquainted with roofing issues (including the dangers) and how to deal with them. Repair or replace? That is always the question. Both options can end up a pretty costly affair but as far as the quality of life is concerned, doing one or the other is worth every cent. So how do you determine the best option for your roof and your situation? Check out this short article on the topic. You might find it useful.

First off, let’s have a look at some of the telltale signs that something is wrong with your roof.

Exterior Signs:

  • Your storm gutters often end up clogged with granules
  • You notice broken tiles or shingles on your roof
  • Your shingles lack granules
  • You notice that the attic insulation is wet
  • Flashing is damaged or missing

You should know that problems with roofing generally occurs on the exterior first, so it is important to be able to recognize any changes in the structure itself. Bear in mind that unless you fix an problems you may find fairly soon, the damage will spread to the inside, making repairs much more difficult and expensive.

Interior Signs:

  • Your wallboards have started to discolor
  • Paint has started peeling or cracking
  • Wallpaper is peeling
  • Mildew or mold has formed on the walls and ceiling
  • Your ceiling has some very suspicious brown spots, the nature of which you are not familiar with

If you miss  the exterior signs, at least make sure you act fast as possible when you discover any of the telltale interior signals  just noted above. The sooner you find a solution, the better. No matter if you currently live in that property, you have rented it out or you are intending to sell it, it is up to you to care for your roof and make sure that it is regularly and routinely cleaned and taken care of. That is unless you want to make all matters worse and end up paying why will probably amount to a king’s ransom for a costly, total replacement.

If you are not sure whether the damage on your roof requires a repair or a total replacement, call  a qualified, licensed local roofing contractor.

When to Repair:

  • If your roof is new (less than 20 years old) depending on the life expectancy of the material and application
  • If the warranty period of the roofing materials has not yet expired
  • If a leak does not reappear once you have it repaired
  • If there is only a small leak that needs repair
  • If this is the first time you have had to hire a contractor to repair your roof

When to Replace:

  • If the warranty period of the roofing material has expired
  • If the roof is too old (over 20 years old or dependent upon the life expectancy of the material/application)
  • If the roof has been repaired a number of times previously
  • If there are leaks found in numerous locations of the structure
  • If leaks keep on reappearing after they are repaired

Unfortunately, sometimes there may not be any visible signs that the roof structure has been damaged and needs repair or replacement. Unless you are an expert at roofing, let a certified, licensed roofing professional inspect the roof. A trusted expert will be able to detect the problems you are facing (if any) and provide the best solution for your situation and one that will make you worry much less.