Building Concepts I Course CMCC- Concrete Slab Foundation Placement Week 4

This short week of class was at no shortage of hard work. The concrete truck was due to arrive with our slab on Wednesday October 14th and we were the students arranged to place the slab inside of the foundation we had been preparing concrete for. We wore rubber boots while we worked the concrete into the corners where we then troweled the mix to our grade (chalk) line that we snapped.   

Here I am working the concrete into the cracks of the corner next to the plastic and foam we have against the wall with a special rake made for moving wet concrete.

In this photo you can see us screeding the concrete. Screeding is the process of using a long piece of metal (usually aluminium or magnesium)  or wood to make back and forth motions across concrete. One or two of us worked the mix behind the screed team to be sure the concrete was at the proper height while its being leveled. Without the man behind the screed you can create pockets where you will then have to go back, fill and re-screed. The people behind the screed are also there to remove what concrete is catching up behind the screed as it can pile up. 

Towards the end of our manual screed job, our instructor for the afternoon showed us the took he was using in the photo below. Its called a power screed, it operates doing the same screeding-job we did, in a fraction of the time with half the manpower necessary.

This tool here is called a Bull Float. What this does is give the surface a clean smooth finished after it has been screeded and still has some ripples from the screed left on its surface. It goes a long pole and is made of magnesium or aluminium so it wont fall into the fresh concrete, it just glides right over it.  

Here we are hand troweling the slab. For this process the concrete had to cure or hydrate for a half hour to forty-five minutes. Hydration is the process that wet concrete goes through while it is hardening up. It does not take long to harden enough to put something to stand on and walk on it. Also here the surface is still malleable enough that we can work with it. Going over the top with trowels like this will gave the surface a clean finish without any large rocks protruding from the top.

Like the screeding exercise, we were shown first how to do it by hand, then by way of a machine that can do it in half the time and with less manpower. The tool that Dave was using in the photo below is a power trowel. It have 4 blades that spin and work the large rock either down or out of the surface face of the concrete slab.

The finished product! It wont be fully cured for another 25 to 30 days but it becomes increasingly  harder every day. By the next day you could walk on it but it wont fully cured for an estimated 25 to 30 days from the day it was placed. 

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Building Concepts I Course CMCC - Footing Forms and Temporary Rain Roof Week 3

This week we jumped around many times a day so the pictures are a bit scattered and unclear probably. We began the week working on our floor framing system, then moved on to cutting insulation for a foundation and laying polyurethane plastic down as a moisture barrier. Today we were assigned the task of cutting roof rafters for a temporary rain prevention system. Wednesday the 15th of October is the day the concrete will be placed for the slab inside of the foundation that has the rafters over it in the picture above. It is a tight schedule and cannot be altered in the event of rain, so we threw together this temporary roof system in the event we would have to tarp over the concrete should it rain next week!   

This video is a pray mantis I found in one of the foundations, moved it to safety or tried too! 

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Building Concepts I Course CMCC: Floor Framing On Foundations Week 2

For this week, we were laid out our mud sills on top of our foundation walls. We used the techniques we were taught in class to find "square- equal lengths, widths and diagonals." Once we have determined our square area then we snap our chalk lines so we have a reference line for our mud sills, a pressure treated piece of lumber that sits on the foundation wall usually supporting floor joist. In reality those sill plates would be pressure treated, however regular kiln dried 2" inch by 6" inch sill plates can be used, without any size differences, for demonstration purposes.

Here in these photos you can see our chalk line where our square is on our foundation wall. The next photo shows also our plate after it was cut and marked for the anchor bolt then drilled with a spade bit for the washer size and a 5/8" inch bit for the anchor bolt. 

In the above and below photos we have marked the center line with a "C and L" symbol for our girder. A girder is a load barring beam running perpendicular to the floor joists. It is what the floor joists will be fastened to in the very middle of the foundation. One of those nails in the photo will be holding a string line that is going to indicate to us if the girder is straight or if it is swinging in one direction or the other.   

Here we are clamping our girder assembly to be nailed, clamping them during the nailing process insures that the boards cannot be separated during the nailing and cup away from the other 2" inch by 8" inch boards. Dimensional lumber has a tendency to do that when it has been fastened together. If nailed a lesser amount the boards can cup, if nailed too far from the edges, the boards can cup. This would be clear from looking at the joints between each board.  

In the photo with the staircase notches are our cuts where the girder will fit sitting on the foundation wall on top of the mud sill. We also setback the wood that will be touching the concrete because concrete has capillary pores that draw water to its driest areas. This process is called capillary action. This result is why we use pressure treated wood as our mud sill.

In the photo above you can see our temporary support "T" posts and the string line running tightly above it.

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New Business Design Logo's coming soon

This is the design I had developed and I will be getting uniform business cards, proposals and invoice sheets. Probably some t-shirts as well! 

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Building Concepts I Course CMCC: Excavation of Garage Foundation Week 1

For our first field assignment for the building concepts course, we were assigned to clear out a foundation that had served as a crude gravel pit. Our goal with this foundation is to pour/ place a slab into it. To do this we needed level off the dirt and using the laser level in the first photo get our point of level in all four corners. Once we found our level points we then increased the height of our chalk line 2 inches at the back half of the "garage." This slope will allow the water to flow away towards the door and no pool inside the building. 

Here we have exposed the footing to use the laser level and draw our line from the back 2 inches off the footer to the front where we will just run the line to the footers. 

After we found our points the very hard working grounds keeper offered to assist us with the removal of the excess dirt.

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