ROOF SYSTEM INSTALLATION

                The roof system discussed herein is a Premier Roof System as opposed to a conventional roof system.  Premier Roof Systems consist of 3x12 ridge beams, 4x8 rafters and collars, 2x6 tongue & groove decking, 15-pound felt vapor barrier, vented roof insulation panels, 7/16” OSB and 6” cap nails.  Air entryways will be incorporated to allow for roof ventilation.  The following sketch illustrates the Premier Roof System:

HOUSE ROOF FRAMING
                To begin installation of the Premier Roof System, first check the blueprints and lay out the roof rafter location by marking the top of the logs with a pencil (see the previous section--SECOND FLOOR SYSTEM for detailed instructions).

                If a shed dormer is to be built, do so before rafter installation and brace off with 2x4’s.  The wall should sit on top of the decking of the second floor system and should be inset properly to allow for 1/2” rigid foam insulation and exterior siding (even with the ends of the second floor joists which were previously inset).  The siding must match properly to the exterior log wall profile.  The following detail illustrates proper shed dormer installation.  After constructing the shed dormer wall, mark the location of rafters which sit on top of this wall.  Also, locate dormers and construct the dormer stud walls.  Mark the location of dormer ridge beams and rafters.

                Again, now is the time to clean, sand and stain (if applicable) your ridge beams and rafters, before installation.  Check your Materials List (copy in blueprints and in warranty packet) to determine size and length of ridge beams and rafters shipped.  Be certain to use the proper length for each application as specified on the materials list.

                From the blueprints, find the location of the ridge beam and get the first piece of ridge in place and braced off.  Use the proper lengths as indicated on the Materials List, and make sure the ridge is level and square with the house.  Join the second piece of ridge beam to the first at the center of a rafter location as shown below.  Fasten ridge beam pieces together as shown above and brace splice underneath with temporary 2x bracing.  Check the blueprints and Materials List as to precise location of splices.  Continue to splice pieces until the entire ridge is in place.  Be sure to keep the ridge level and square with the home and properly braced.

                Valley rafters will then need to be installed (if applicable) and are usually 3x12 material as well.  Study the blueprints for precise location.  Check your Materials List as well to make sure you use the correct lengths of material.

                Once the ridge beam is in its proper place, mark the location of rafters on the ridge bam.  Make sure these locations correspond to locations previously marked on the top of the log walls.  Rafter centers must join the ridge beam directly across from one another.

                You are now ready to begin installing the rafters.  Chisel away the tongues on top of the log where the rafters will sit.  Rafters should sit on the log top, not on the tongues.  It is best to get rafter measurements and precut rafters on the subfloor or ground before installing.  2x8’s can be used to make templates by actually holding 2x8 in place at different locations and marking the proepr cuts.  Then use the 2x8 to mark the 4x8 rafters.  Do not cut all rafters until you are sure the cuts are right!  Use proper “bird’s mouth” cuts to allow rafters to sit flat on second floor or log wall.   Allow for the house roof overhang except where covered porches are to be installed.  Under porch roofs, rafters should be cut flush with the ends of the second floor joists to allow exterior siding to be installed and match up to the exterior log wall profile.

RAFTER COLLAR INSTALLATION

                After all rafters are in place, rafter collar ties should be installed.  Collars are important, as they keep rafters from pushing out on the log walls and from sagging in their middle.  Collars are attached to the rafters by using 2x8 lumber to ‘scab’ the rafter and collar together with metal banding underneath.

                Clean, sand, and stain (if applicable) the rafter collars andscabbing materials efore installing.  Furthermore, create a decorative finished look by using a drill and 1” butterfly bit to counter sink holes in the scabs.  The scabs will be attached to thecollars and rafters by nailing through these holes.  The holes will later be plugged with short pieces of 1” diameter dowel rod, giving the appearance that the collars and rafters are doweled together.  Prepare the scabs by cutting pieces to length and drilling holes in a consistent pattern.  A minimum of ten 16-penny nails per scab must be used.  Larger size nails and/or lag screws are recommended.

                Mark collar locations on rafters, get measurements, and make necessary cuts to collars.  As a rule of thumb, collars over a second floor should be eight feet above the top of the log walls.  Otherwise, collar locations can be determined as follows:  Measure the distance from the top of the log wall up to the ridge beam.  Take 1/3 of the distance you measured and add it to the height of the log wall to determine the height of the collar.

                Prepare scabbing material (2x8) to secure collars to rafters and attach two scabs to one face of each collar.  Hold the collar in place between the two rafters and attach by nailing the attached scabs to the rafters.  Once the collar is in place, you should install the two scabs to the other face of the collar.  But first, tie the collar to each rafter using metal banding.  Then install scabs by nailing to the collar and the rafter over the metal banding.  Rafter collar ties should be installed before the2x6 tongue & groove decking is applied to the roof framing.  Do not use rafter collars with the barge rafters or the rafters directly over log walls.

                Once again, it is time to consider electrical wiring for any overhead lights or fans that will be installed in the second floor ceiling (roof).  You may have reason to recess wiring into the tops of some rafters before installing the roof decking.  However, it is easier to run wiring over the top of the 2x6 tongue & groove decking.  The wiring will then be covered with the insulation panels (have your electrician supervise any and all wiring runs).  After all rafters are installed and any necessary wiring is run, you may complete the installation ofyour second foor tongue & groove decking.

GABLE STUDWALL CONSTRUCTION

                You should frame your gable walls at this time, before installing roof decking.  The gable wall will sit on top of the end log wall.  Use 2x6 or2x4 framing to construct a studwall with the top plate of the studwall being the same height as the rafters.  Be certain to calculate the proper thickness needed for the 2x studwall framing.  Exterior siding and 1/2 inch rigid insulation will be applied to the outside of this wall.  The exterior siding must properly match the exterior log wall profile underneath it.  Furthermore, consider the interior wall sheathing.  For instance, if there is no second floor system at this gable, you may desire interior sheeting (sheet rock, 1x8 T & G, etc.) to fit flush with the interior of the log wall below it.  Carefully calculate the 2x thickness needed and construct the gable end studwall with the proper width.

HOUSE ROOF TONGUE & GROOVE DECKING INSTALLATION

                You are now ready to install the roof sheathing, usually 2x6 tongue & groove.  Tongue & groove roof decking should be face nailed into each rafter with two 16-penny coated nails.  Do not nail through any wiring in the top of your rafters.  Nail each piece of tongue & groove into every rafter it sits upon.

                Begin on the low end of the rafters.  Rip the tongue or groove off the first piece to give a vertical cut when laid perpendicularly across the top of the rafters.  Make this edge flush with the ends  of the rafters for future fascia installation.

                Air entryways for ventilated roof systems must be installed at the beginning of the roof decking installation.  It is usually installed in the second or third course of decking of the overhang areas as shown on the next two pages.  Air entryways for ventilated roof systems under covered porches may be installed in the manner shown on pages 70 and 71.

                Under porch roofs, tongue & groove decking should run to the inside edge of the house rafters.  The tongue OR groove should be ripped off the outer piece of decking so that a flat edge will exist on the outer piece.  When installed, this edge should be vertical and flush with the house rafters.

                After installing the tongue and groove roof decking, you should apply a vapor barrier on top of the roof deck.  Use 15# or 30# felt or a 4 mil. clear plastic sheeting and attach with 7/8” plastic top cap nail or staples.

                At this point, before installing roof insulation panels, you should run electrical wiring over the top of the tongue & groove decking if needed.  Have your electrician present to supervise this installation.  Wiring for overhead lights and fans and the like should be installed now.  Also, before roof insulation is installed, the porch roof should be framed and decked.

PORCH ROOF FRAMING

                The porch roof discussed herein is a shed type roof attached to the house roof and consists of the following members:  porch roof support posts, 4x8 plate around tops of posts, 4x8 porch rafters and 2x6 tongue & groove decking.  The porch roof should be framed after the porch deck is built.  (See details under previous section on subfloor).  The following illustrations show the proper method for framing a Premier porch roof.

                The first step in porch roof framing is to lay out the porch roof support posts.  Either square or round posts should be installed on top of the porch deck and located directly over deck supports.  Posts should be properly supported underneath the porch floor decking.  Review the previous section on Porch Deck Construction if necessary.  Clean, sand and stain porch posts before installation.  Also, make the proper cuts in the top of the posts to accommodate the 4x8top porch plate as shown.  The posts shold be cut to be 7’tall, and the following illustrations show the proper cuts.  If you prefer a look with the porch rafters not setting as high on the house roof, the porch posts can be trimmed to bring the whole level of the porch roof down as much as desired.

                Porch post centers are generally located 8’ to 12’ apart on the porch deck.  Window and door location may affect your post locations.  However, check your blueprints for exact post locations and set the posts in their proper location.  Toenail the bottom of each post to the porch deck and brace the posts off with 2x4’s or other bracing material.  Make sure posts are vertically plumb.  Also, be certain that the posts are placed in a square fashion so theporch roof is square.  Even if the porch deck is out of square, the porch roof must be suqare with the house roof.

                Once all posts are installed and braced and are square and plumb, you are ready to install the top porch plate.  Clean, sand and stain 4x8’s to be used for the porch plate.  Use the proper lengths as specified on the Materials List.  All splices in the 4x8 top plate must be located over porch posts, and the plate shoudl be attached to the posts with lag bolts.

                After the plate is properly installed, mark the plate for porch rafter locations.  Porch rafters should sit on the house roof directly above thehouse rafters.  See your blueprints for exact rafter locations.  Mark the house roof for porch rafter locations.  Using the proper porch roof pitch from the blueprints, cut a porch rafter to length, allowing a minimum 16-inch overhang off the front of the porch.  Make sure the rafter is properly cut before cutting other rafters.  Also, do not cut all the rafters the exact same way if the porch roof framing is not perfectly square.  Porch rafters should be toe-nailed in place until all are installed.  Once all rafters are properly located, use 10” spikes to permanently attach rafters to the house roof and to the porch plate.

                Do not install 2x6 tongue & groove decking to porch rafters until the house roof has been insulated.

ROOF SYSTEM INSULATION

                The following diagram illustrates how the roof insulation should be installed to allow for ventilation.  Air flow is to take place on the top side of the insulation, not the bottom.  The flat side of the insulation panels should be turned down when installed.

                You must build 2x blocking around the perimeter of your roof, keeping the outer edge flush with rafters to allow for eventual fascia installation.  Furthermore, you should put a strip of blocking every three feet or so along your overhang areas to prevent insulation panels from covering up your air entryways.  Also, you do not need to insulate overhang areas.  Be sure your blocking is the same thickness as the roof insulation panel so the OSB will lay flush across the entire roof area when applied.

                Once perimeter blocking is in place, lay a run of insulation panels across the roof.  Butt panels tightly together as you go across keeping panel ridges joining ridges and valleys joining valleys.  Use the Manufacturer’s Installation Manual for more detailed instructions.  Cut panels with a circular saw to fit.  Cut at proper angles at valleys, rafters, etc. and keep a tight fit between panels.  After laying this run of panels, install 7/16” OSB on top by nailing in the pattern shown in the Insulation Panel Manufacturer’s Installation Manual.  Use the 5-1/2” panel screws provided to secure the OSB and insulation panel to the roof decking.  The screws will go through the OSB, roof panel, vapor barrier, and into the 2x6 decking.  Keep edges of the OSB flush with rafters so that fascia will fit properly when installed.

                Continue installing the panels and OSB in this manner until the entire roof area is covered.  Leave a gap at the ridge (approximately 2 inches horizontally) to allow airflow to escape through a ridge vent to be installed with your finished roofing material.  Roofing felt should then be installed on top of the OSB.  The instructions provided in this Construction Guide are brief.  The Installation Manual provided by the Insulation Panel Manufacturer should be followed carefully.

PORCH ROOF DECKING INSTALLATION

                You are now ready to install the 2x6 tongue & groove decking on the porch roof rafters.  Begin at the front edge of the porch.  Rip pieces of tongue or groove at the angle of your porch roof pitch for your first horizontal run of decking.  Install the flat edge of these ripped pieces toward the front and keep flush with the ends of the porch rafters.  This allows fascia boards to be nailed later over the rafters and tongue & groove decking.  Butt pieces together over rafter centers and alternate joints.  Face nail the decking using the proper nail pattern as with the house roof decking.

                Apply decking all the way up to the house roof. Cut the last horizontal run of tongue & groove to fit tightly against the top of the OSB sheathing on the house roof.  Try not to leave a gap in the decking where the porch roof joins the house roof.  If you do not have a hard surface where the two roofs join, shingles, to be installed later, may be easily broken when stepped on.  Do not block air entryways or airflow of the ventilated roof insulation system.

                After the 2x6 tongue & groove is installed, cover the decking with a vapor barrier.  Use 15# or 30# felt or a 4-mil. clear plastic and attach with plastic-top cap nails or staples.  Porch roofs are not to be insulated.

                If you wish to have any overhead lights, fans, etc. under the porch roof, run your wiring over the top of the porch roof decking or recess wiring into the tops of the porch rafters before installing decking.  Drill through rafters to bring wiring out under the porch roof.  Have your electrician approve your wiring.  Your porch roof and house roof are now ready for finished roofing.