Even though the Quonset hut was bolted down, the steel arch shape hut does not really achieve its design strength until it is grouted in place. With winter coming, I was under pressure to get it done quickly before the temperature dropped and the snow storms rolled in.
It is actually possible for concrete mix additives, such as plasticizers or accelerators, to accelerate the curing reaction so it will set in colder weather, but, the SteelMaster Quonset installation manual warned that such mixtures may be corrosive. Calcium Chloride, specifically, is known to release steel corroding chloride ions and should never be used with rebar, let alone the thin 20 gage steel of the Quonset hut.
The weather was generally too cold by that point, so I had bought a couple propane heaters and decided to get started before it got any colder. But then the weather changed and the forcast was for several days with highs above 50°F and lows above freezing. I headed out to the property to take care of this job…
My grout mix was a simple 2:1 ratio of sand to Portland cement. I bought the 94 lb bags of Portland cement for ~10$ each. I already had lots of nice clean sand on site (my hill is made of it), so I just used the skid steer to bring some over to where I was mixing. Creating the mix with my own sand saved me hundreds of dollars over buying pre-mixed bags of cement. The third ingredient was water… I have no access to water on the site, but I had brought a number of 5 gallon buckets full of water with me. I did not use any additives.
I have often mixed small batches of concrete in a mixing tray or wheel barrow for odd jobs around the house. My biggest manual mix had been a couple sidewalk squares. But in this case, I knew I had about ¾ of a cubic yard to mix, and I knew that I would have lots of other concrete and stucco mixing jobs, so I decided to buy a mixer. I had been keeping my eye out for one for a while and ended up getting a decent 3.5 cu. ft. ¾ horse power electric cement mixer, on sale for 40% off. The majority is metal, but the barrel is a strong thick plastic that won’t rust on me. I paid about $200 dollars, but I am sure it will be worth it. Just the time it saved me on this one project probably made it worth it to me ;^)
Once I was all setup, I used a shovel to measure out the mix and then added water until it reached the right consistency. Ideally, the concrete should be sticking well to its self, and not to the mixer. However, until it was fully mixed, I was using a small shovel or the trowel to scrape off the sides and keep everything mixing.
I used a 3 gallon bucket to carry the mixed grout to where it was needed.
With the shorter days, of November, it wasn’t long before the sun set and I was very glad to have my work lights… However, the work-lights and mixer were quite a strain on my generator and it nearly stopped a few times, leaving me momentarily in the dark.
Near the end, when I was worried that I might be a little short of concrete, I started adding some scrap rigid insulation as a volume filler. I probably should have thought to do that from the start.
When you are building a house, not all the days are big days… There are lots of “odd job” days. I don’t usually setup my camera, and when I do, the footage is not usually interesting enough for a post of its own, but I thought I show a collage of odd-job days to document the gist of it.
A little more detail:
The hardest part about these odd jobs is just to find the time for the drive out to the property. Now that the weather is cooler and I am pretty much out of vacation days, I usually wait for a warm enough day and head out to the property after work. But the days are getting shorter, so after I drive an hour to get there, I only manage to put in a couple hours of work before the sun sets. I bought some work lights to extend my time a bit before I need to pack up and head back.
As winter approaches, working around the weather is quite a challenge. The concrete weather proofing, grouting and other tasks often have a minimum temperature for correct application.
I really wanted to get the Quonset hut up sooner, but there were delivery delays. It was eventually delivered just before I had to take a 2 week business trip. I had to protect the delivery from the weather while I was away, so I laid out some plastic to keep it dry. I put the plastic down first and set the steel (all on one skid) on top of it and then folded the plastic over like a taco… The plastic at the bottom keeps the moisture from coming up out of the ground, the plastic on top sheds the rain, and the open sides were to let any moisture that did get in, get out again. I screwed wood strips on both sides of the plastic to keep in its place while I was away… It worked.
We were also in a rush to get rye grass growing before the weather got too cold for it. Actually, fall is the best time to plant grass (the air is cool, but the earth is warm), but I would have liked to start it closer to Labor Day. Sherri planted and raked in most of the seed, but I got in some rake time when I could.
The garage ends also needed insulation against the footings. The basic idea behind “Shallow Frost Protected Footings” is to thermally separate the soil under the footings from the cold air in winter so that ice “lenses” don’t form and push up the footings. The normal solution is to put the base of the footings below the “frost line”, about 4 ft deep in my area. Temperature change happens by conduction, so it doesn’t really matter how “deep” the footings are, the insulation creates a longer path for the conduction and keeps the footings warm. This building code exception to normal building practice allowed me to save a lot of money because I didn’t need to dig the footings as deep and use all that extra digging, concrete and money. Adding on this insulation is a small price to pay. Although, technically, my sandy soil means I don’t really have to worry about frost heave, the insulation is still helpful in keeping the garage temperature more stable.
This last job in the video was just cleanup… We (and the various crews who came to work on the site) had been stacking used wood and rebar on side of the building site. Now we needed to backfill that area and it was time to get that stuff out of the way. We also wanted to protect the better wood and put in under the Quonset hut. Many hands make light work… So Sherri and the boys came out to help. I really appreciate my crew.