Valleys

Roof valley installation procedures with diagrams

 Shingle Valleys are one of the most complicated and least understood details of a shingle roof. Often valleys are where problems will occour on a shingle roof. There are several different valley application types, and while all are good, some are better for different situations.We will go over some of these types of application procedures, and address some of the strengths and weaknesses of these types. Valleys are referred to as either a closed or open valley.                                                            Closed Cut Valley
This method is preferred by most shingle manufacturers, and old school roofers in most roofing applications, except when using certain types of high end lifetime shingles. Or when valley is at 80 degree angle

  • First you will want to determine which side of the valley that you want to run the shingles up onto, and which side that you will cut. The side of the valley with the least amount of water shed should be applied first, then the shingles that will be shedding a greater amount of water will be the cut side of your valley
  • Of course you will always want an ice and watershield type of underlayment applied into your valley to start with
  • Now you will weave or interlace your first course of shingles. Note; This is a very important step in preventing leaks, and this procedure should be used in ALL closed cut valley applications
  • Lay your second course of shingle across the valley and extending 12” up the other side of the valley. Follow standard fastening procedures except, be sure not to put any fasteners closer than 6” away from the valleys center
  • Follow the same procedure for each additional shingle going up the valley until you reach the top of your valley
  • Apply the shingles on the otherside of the  so that the exposure of the shingle will cover the center of the valley
  •  Next pop a chalk line 2” away from the last side of the valley youve installed. procede to cut the top layer of shingles along the calkline taking care as to not cut the bottom layer of shingles. You should also “dub” the tops of your cut shingles at a 45 degree angle. Note; Using a hook blade on shingles requires no downward force into the roof, simply put the hook blade where you want to cut and simply pull the blade, that is the reason its a hook blade. Remember hook and pull.

Notice the first shingle of the least shedding roof plain has been ran underneath. This is a good thing.

Woven Valley
  • Ice and watershield or a similar underlayment should be applied into valley
  • Apply first course of shingles on either side up adjoining valley 12”
  • Follow standard fastening procedures except making sure to nail 6” away from valley centerline
  • Over lap first course of shingles on other side onto first side 12”
  • Apply second course of shingles on first side up valley by 12” and vise versa until at the top of valley


  

                                                       Alternative or California closed valley
This installation method is very popular in new construction as well as with the younger generation of roofers.

  • Ice and watershield or a similar product should be placed into valley
  • Weave or interlace your first course of shingles on both sides of valley. Note; This is a very important step in preventing leaks, and this procedure should be used in ALL closed cut valley applications
  • Install shingles up valley with lowest water shedding flow first. Make sure shingles go up the adjoining valley 12” at the top of the exposure.
  • Fasten shingles using standard nailing pattern. Be sure not to nail within 6” of valley centerline.
  • On the other side of valley pop a chalk line 2” out of valley the entire length of valley.
  • Use chalk line as a guide and install a course of shingles vertically up roof, nailing at least 8” out of center of valley
  • If installing a three tab shingle, the shingles running up the valley chalkline must be upside down
                                                     Open valley application

  • Ice and water shield or a material that is equivalent should be applied to valley
  • Install 18” or 20” wide sheets of preformed metal valley into valley. Sheets should overlap each other by at least 4”
  • Use clips to fasten valley metal so that there are no penetrations into valley metal
  • Pop a chalk line 3” from center of valley and cut shingles along this line as the shingles are applied
  • Install shingles into valley cutting the shingles along chalkline as they are being installed
  • Fasten shingles in a standard procedure, taking care as to not penetrate valley metal