BCT 144 Structural Analysis Assignment

Setting

The joys of owning a dishwasher. The ease, simplicity and time saved by stuffing all of our dishes away in this little cube. This little, unassuming cube... that sprang a leak. Under our floor. For what may have been weeks. One morning I am taking dishes out of our sink, and putting them into the dishwasher for a cleaning, when I realize suddenly, the floor is spongy under my feet. Squishing even, literally like a sponge and when I get down for an alarmed, close inspection the smell. Musty, like a wet basement. I rip open all of the cupboards underneath the sink and counter, looking for the culprit, sure that the sink has sprung a leak. But I can't find the source. And then I look to my left, eyeing the dishwasher. I pull it out. Sure enough, damp wet and newly molding laminate confirms that the dishwasher is the offender. 

Structural Issue

Now, our landlord came over promptly and removed the dishwasher, ripped up all of the laminate flooring in the area and brought in blowers and dehumidifiers to dry the space out. The underlayment was ruined, this thin particle board that absorbed a significant amount of moisture and swelled, pushing the laminate tongue and groove out of place, buckling and cupping.

Cupping Floorboards 

Floorboards spreading apart, due to the underlayment swelling

Photo taken underneath, from the crawlspace. I'm not sure what the purpose of the foam was, but this torn opening is the only place it exists in. I believe my landlord opened this space to see what damage the water had done, and then put this foam in place to hold the insulation in... You can see residual water damage on the foam itself - although this could be from exposure to the crawlspace, but that would also expose the insulation, and floor system to the moisture present in the crawlspace during the summer months, resulting in... mold and water damage...

Exaggerated example of laminate flooring cupping. Much easier to see with the level and tape for reference.

The underlayment was never removed. What further damage was done beneath it still remains a mystery. The possibilities are:

• Mold and Mildew are growing in our living space.
• The sub floor may have been damaged, warped or had it's structural integrity ruined.
• The floor joists themselves may have been exposed to water, allowing them to rot and putting everyone who walks on that part of the floor in danger, if they happen to give way.

I believe this is a structural issue because the flooring, sub floor and entire floor system (in this area of the house) may have had it's ability to support the amount of load it was originally designed to hold damaged by water and, subsequently, rot. (IRC R501.2) Sub flooring that has had it's integrity damaged may not be able to support the loads required of it originally (IRC Table R503.2.1(1)).

Work proposal

Ignorance is never bliss. Living in a house with unknown conditions is a recipe for accidents and a multitude of other issues. At the very least, an inspection of the sub floor and joists should be done. Depending on what this inspection reveals, the sub flooring and, possibly, some of the floor joists may need to be replaced (along with parts of the floor system that are already visibly damaged - the laminate flooring and sub floor underlayment.)

For this project I would need the following tools:

• Wonder bar or larger pry bar
• Tape measure 
• Hammer
• Speed square
• Level
• Circular saw or Skilsaw
• Impact Driver and Drill
• Pencil
• Safety glasses
• Dust mask
• Sawzall
• Flashlight/Work light
• 16d Nails

Step 1: Pull up the laminate flooring and underlayment

Step 2: Identify where the water damage extends to in the sub floor

Step 3: Cut out and remove whole sheets that contain ANY water damage

Step 4: Inspect underlying joists

Step 5: If joists also need to be replaced, install them next to the rotten joists

Step 6: Cut out rotten joists and dispose of them

Step 7: Install new sub floor sheets

Step 8: Install new underlayment

Step 9: Install usable laminate flooring and new laminate flooring

Although this repair would most likely only take up to a day to complete, the work being done should be completed while there are no other occupants in the house - there may be negative impacts to occupants. The mold/fungi spores that may be released into the air during deconstruction/construction may be harmful to all individuals. A HEPA filter should be used while the project takes place and I would be wearing a dust/mold mask. The area will need to be sanitized thoroughly after the project is completed. Also, other hazards to occupants exist: There will be an opening in the floor through which individuals may fall. There may be enough debris over which someone could trip.

Material Estimate

Item	Description	Qty	Unit Measurement	Unit Cost	Extended Cost
Flooring	Laminate 8mm, Oak Brown	72	sq ft	$1.69	$121.68
Underlayment	100 sq ft roll Serenity Foam	1	100 sqft roll	$14.97	$14.97
Subfloor	Advantech OSB 3/4"	3	32 sq ft sheets	$16.28	$48.84
2x8x8 Floor Joist	No.2 Pine 8'	9	8 foot board	$5.96	$53.64
16d Nails	Steel Sinker 3 1/2"	1	5 lb bucket	$9.87	$9.87
Total					$249.00

Labor Estimate

# of Days	# of Workers	Total Man hours	Rate per Hour	Total Labor
1	1	8	$20.00	$160.00*
Project Total				$409.00

Conclusion

I believe that the total cost of this project is perfectly reasonable. When weighing the possible cons associated with the health risks of living with mold, and having the unknown possibility of the floor system collapsing under us, $409.00 is far cheaper than any hospital bill. I feel comfortable doing this project myself, it is straightforward enough, does not require any special equipment and can be done in a day. As a beginning carpenter, it could even be the perfect first project.

* Labor cost would be negligible if the repairs were performed by myself. True cost of the project would therefor be $249.00.

Week 21: March 20 - 26

Week 21, the first picture above is of our dormer mock up. Not too much progress made at the moment, this week was a testing week so we were busy with other things. But we did make it as far as getting all the gable end studs up.

I wanted to talk a little bit about some of the different types of house wraps we're using. Featured above, from left to right, is HydroGap and Blueskin VP100. HydroGap has a built in drainage plane feature. This means that furring is technically unnecessary, as the amount of space required for water to shed behind any type of siding is already built in.

Blueskin is a self-adhering house wrap. It comes in 4", 6", 9", 12" and 48" roll width sizes, lengths of 100'. This product is interesting, because it allows application of the product without additional penetration of the building envelope (with fastners). It creates a completely air and water tight seal, although in the literature it does state that it is a vapor permeable barrier... It comes with a 12 month warranty, but only if the product is truly defective. 

Here I have one picture of all of the corner boards that have gone up on the sheds. I haven't had a personal hand in constructing these, but I was noting in the picture the notching that needed to happen up at the soffit, so that the corner board looks like a complete assembly. The corner boards are furred out 3/8 - 1/2", dependent on what type of siding will be used. The corner boards are kreg drilled and glued together, with the front facing board being the full width, and the side board (of the complete assembly) being it's width minus the thickness of the adjoining board.

And here, in the later part of the week, I was working on installing a window. Pictured above is the window RO (Rough Opening), with the correct window to be installed positioned below. I first cut the Typar House wrap out of the window opening, and cut the top at 45 degree angles away from the window opening, so that the flap could be lifted up and taped down over the window once it is installed.

Here I have a shingle cut to the RO width. This will aid in water drainage (in the correct direction: OUT), angling and trapped water out and away from the house. Water penetration is the biggest issue to combat when making any hole in the building envelope.

And here I have the window caulked and tacked in place (with galvanized roofing nails = no rust). Underneath the window, you can see the Grace Vycor Plus that I used to flash the window. When flashing, I cut 'bow ties', or angled strips that sealed the lower corners of the window RO first. Then a 34" strip was cut for the complete lower panel flashing. 24" for the RO, + 5" for each side. The extra on each side was run up the inside of the window RO. Slits were cut 3" deep in the roll and 5" in, allowing us to bend the Vycor down and over the window furring and housewrap.

Week 20 March 6 - 12

Catching up here on some things from Week 19, painting the exterior trim of our 10 x 12 shed.

Here I am laying out the rafters on the top plate of our wall.

Cutting the rafter pattern with the miter saw so that we would have the straightest, truest cuts to trace onto all of the other rafters.

Finish cutting out the rafter tails with my handsaw.

Using my skill saw to notch out the end of the rafters, for the fascia to sit below the crown molding.

And finally, the beginning of week 20 here. The 10 x 12 shed is completely wrapped in Typar house wrap. I will post pictures of the other types of house wraps in the next weeks post.

Here I have bracing inside or our dormer mock up shed. This will make it easier for us to do sheathing and all of our exterior work, without having to worry about anything being in the way. We also used this bracing to shift the ridge so it would be plumb.

The LSL lumber we are using to frame the window openings.

Notch cutting for the gable end studs. 1 1/2" deep with a roughly 45 degree angle.

And finally the back wall of the shed with all of the gable stud framing in place! Happy Spring Break!

Week 19: February 28 - March 5

Week 19 I am laying out rafter tails in the design drawings above. These rafter tails vary away from the common rafters we have been practicing frequently, and even the hip and valley rafters we spent a considerable amount of time on. What we're trying to accomplish, with all of these different pieces shown, is a rafter tail that will support crown molding.

The 5/8" plywood on top (top referring to rafter orientation, the plywood is actually all the way to the left) is standing in as a mockup for the roof deck that would be on top of these rafters once assembled. The thin piece of a block that lies flat represents the crown molding. The thicker block that lies just below that represents the fascia.

The dormer mock up shed we're working on, This shed has an 11/12 pitch roof and will have a dormer framed on either side. In This picture we have the rafters and ridge board installed, as well as some bracing to keep the whole system from racking back and forth.

A picture of our rafter tails. I was getting a lot of questions in class as to why the tails looked so weird, but again, referring to the pictures above of the sheathing, crown molding and fascia system, this is the way that the system presents on the end of the rafter tail. The first almost 90 degree (to the rafter tail itself) run downward supports the crown molding. The v cut in the center (the lower portion) will support the fascia, while there will be sheathing above and below the rafter tails we will place the soffit.

Here I am using a bar clamp to pull this rafter back down, so it will be firmly seated on the plate. With it clamped in place, I was able to re screw the birds mouth in place.

Week 18: February 21-27

 

Week 18, I did a little work in and outside of the shed. Here I've put collar ties in place. These boards prevent the walls from spreading, which they are inclined to do, due to the downward/outward force of the rafters. You can see the angled cut, allowing the board to flush up with the outside edge of the top plate (framing).

The collar ties are spread 4 feet apart. Because the shed is only 12 feet long, only two collar ties are needed.

 

In this picture I've moved onto putting the drip edge back in place. Before taking it off (it was previously fitted in place), I numbered each part in the order it would be reassembled. Some work did need to be done to get the pieces fitted well together.

 

Here I am cutting shingles and starting the first course. Using a piece of plywood and a straightedge, I cut the first course of shingles (which are 3-tabs), removing the tabs. These were placed along the entirety of the first course, and then we placed architectural shingles over the starter course, flushing the architectural starter course with the 3-tab starter course.

Nailing the shingles in place, we were careful to offset our second course of shingles by 10", the third by 20", and the fourth by 30". This ensures that our nailing schedule never comes into conflict with any other nails. All nailing is 1" in from both sides, and then a third of a full course length in from each end, another nail is driven along the nailing line. (Each shingle tab has a visible chalk line, for nailing.)

 

Here I have five courses of shingles up.

 

Every couple of courses, we like to snap a chalk line. This ensures that we are still running courses that are true, not skewed, or running off course.

 

Here we are putting the ridge vent in place. First we snapped chalk lines, half the width of the ridge vent, down from the peak of the drip edge (where it meets at the ridge.), on both sides. This allows us to line up the ridge vent, along it's entire run.

And here we are nailing the vent in place, with galvanized nails.

Week 17: February 14-20

Week 17 is a short week, Monday was President's Day, so there was no school, which means no work. On Wednesday we came back and started putting up staging so the roof of our sheds would be more accessible.

After the staging was up, we swept off the deck thoroughly, measured up from the eaves 17 1/2" (the width of the Grace Ice and Water Shield, minus a 1/2" that extends down over the eaves. This aids in water run-off), and snapped a chalk line for referencing.

Here we are applying the Grace Ice and Water Shield. This is primarily for practice, as there is no practical application to putting material on a building with no true thermal envelope. Without heat, there is minimal risk of ice dam buildup. Heat is required to melt ice that would settle on the roof, allowing it to flow down to a lower, cooler point. There it would refreeze, having potential to cause major damage to the roof and underlying members (and insulation.).

Here we have felt underlayment down, getting ready to install our shingles. The nails are specially equipped with orange washers, which prevent the nails from being sunk to deeply, and more effectively pin the roof wrap in place.

And here in this last picture, you can see the felt overlapping the Grace Ice and Water Shield. Everything on the roof is worked from the eaves up, so as to make sure all materials overlap the previous lower material. This ensures that all water run off will be directed down and off the building in an efficient manner.