Monday, March 22, 2021

Construction - Drywalling

Drywalling has been ongoing since the summer of 2020.  While this post contains some new information, it also overlaps the previous post on rice hull insulation.

Atypical Sequencing For The Drywall
The sequence I am following for drywalling is dictated by the use of rice hulls for insulation and having to work largely alone during the early months of COVID-19.

The interior partitions were drywalled first followed by the exterior walls and ceilings starting 
with the lower drywall course on the walls followed by the higher courses then on to the
ceiling one course at a time (as shown in the picture).  By positioning the insulation blower (blue object in the center of the picture) at the foot of the temporary steps, all areas of house could be reached with its hose without moving the blower.

The industry standard is to drywall the ceilings first then the walls where the panels are hung horizontally starting at the top and working towards the floor with the top panel supporting the edge of the ceiling panel.  I am doing the opposite -- hanging the walls first starting at the floor followed by the ceiling. Since cutting the second or, in some cases, third course of wall panels at just the right height to support the ceiling panels is impractical if not almost impossible, I had already added nailers to the tops of the partitions to which the edges of the ceiling panels could be screwed for added support between trusses.  Instead of drywalling the entire house in a random fashion, we concentrated first on the interior walls and ceilings that will not be insulated -- bathrooms, closets, bedrooms, kitchen, dining room and living room.  The reason for delaying drywalling and insulating the shell of the house until colder weather was to allow time for the thermal mass to store summer heat one last time.

Fortunately, I could hang most of the wall panels working alone with the help of custom jigs in lieu of a second pair of hands.  For the longest panels on the second tier, I could call my wife, Dorothy, to come over from our residence next door to help.  By mid-fall, with periodic COVID testing and masking, we felt comfortable accepting help from two family members with handy skills.

Drywalling the Insulated Exterior Walls and Ceilings
The 15" thick exterior walls were drywalled one course high then filled with rice hull insulation.  We then hung the second course of drywall and filled behind it by working through the duel top plates.  The top of the wall was filled to overflowing before the first course of drywall was hung on the ceiling next to the wall and filled with hulls in order to be sure that the junction between the wall and ceiling was tightly packed.  After the first ceiling course was filled as much as possible without spilling over the edge, the second course was hung and similarly filled with hulls.  This pattern of hanging one course of ceiling drywall at a time then following with the rice hulls continued up the cathedral ceilings until the opposite wall was reached for both the first and second floors.  Segmenting the ceiling work to one drywall course afforded the opportunity to use a "T" shaped plunger made from 2 x 4s to pack the hulls as they went in, thereby eliminating any voids.

The cut-outs for pipes and electric boxes in the exterior walls and ceilings had to be handled differently with rice hulls.  Extra effort was needed to minimize the size of gaps between the drywall and a pipe or box and the holes for the wires in the back of boxes have to be occluded as well.  Otherwise, the hulls are forced through them when the insulation is blown and would probably leak out ever afterwards.  A few larger cracks were filled with minimal-expanding foam, particularly around ceiling boxes whereby the foam will be hidden under the shroud for light fixtures or ceiling fans.  A couple of larger cracks around wall boxes were filled with non-shrinking plaster-of-Paris.  As explained in a previous post, smaller gaps around some wall boxes were sealed with Zip tape including using an undersized switch plate as a guide for trimming so that the edge of the tape would be hidden under a full sized plate.   

Helpful Techniques
I had done a modicum of drywalling in the past and thought that I was reasonably good at it, that is, until I  researched the subject in earnest. 

In the end, though, all I really needed in the way of enough information to upgrade my skills sufficiently was Myron Ferguson's book, Drywall.  Following are a couple of his hints that were especially helpful when hanging the walls.

When hanging large sheets on walls working alone, he suggests starting a nail where you knew it would hit a stud then lifting the panel to place and driving the nail to hold the panel until it could be properly fastened with screws.  

A second hint was a nugget -- an easy and accurate way to cut around electrical boxes and plumbing pipes, at least for the lower course of drywall -- without time-consuming measuring and cutting before hanging the panel.   First use a carpenter's square or a spirit level to mark the coordinates of each box or pipe on the floor then hang the panel with a few screws at the top.  Using the coordinates, it is then easy to zero in on the hidden box and cut around it with the tool of my choice, an oscillating tool.  When done right, the space between the box and the drywall was essentially only the thickness of the oscillating blade which, I would like to think is enough to satisfy most drywall tapers' wildest dreams, as opposed to the cruder cuts made by the thicker blade of a punch saw or the rotating blade of a drywall router, to say nothing regarding inaccurate holes precut from measurements.  When the panel is free to slip to place around the box without forcing, it can be screwed to place.

Taping the Joints
Morrison also had four recommendations for locating the joints between panels.  First, whenever possible, run the panels horizontally and, if running them vertically, only do so when the panels reach uninterruptedly from floor to ceiling -- say, 8' panels for 8' ceilings.  In either case, the most conspicuous joints are formed by the sides of the panels that are tapered and designed for taping.  The advantage of running the panels horizontally is that it increases the strength of the wall.  A second Morrison suggestion:  when butt joints (those at the ends of panels which are not tapered) cannot be avoided, they should be located near the corners of a room where the additional bulk of joint compound is less likely to be noticed.  His third suggestion is to avoid butt joints near doors and windows where the extra thickness of compound invariably compromises or complicates the fit of casement molding.  Instead, cover doors and windows with long pieces of drywall and expose the opening after fastening.  The latter is best done by sawing the sides of the opening and using a knife at the top of the opening to cut the paper on the backside then breaking the piece before cutting the paper on the front side to free it.  With window openings in conventional walls, the top cut must be made before the panel is installed but, in our case, the walls were so thick that the window openings could be handled like doorways, i.e., reaching in to cut the back side at the top after the sides had been cut with a saw.

Since I did not intend to do the taping myself, I was motivated to take as much care as possible to make the drywall look like it was hung professionally, especially when cutting around electrical boxes and plumbing stub outs and butting at the corners.  I also took responsibility for installing the metal corner bead on outside corners.  The final step was to drag a wide taping knife over the surfaces of the drywall in conjunction with inspecting it visually to find and fix any screws that were not properly countersunk.  The last thing I wanted to do was to cause a taper to raise his or her price to cover sloppy hanging or to be unwilling to work with a DIYer at all.

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