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Sean Kollee
  • Investor
  • calgary, alberta
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inner city duplex part 9-12

Sean Kollee
  • Investor
  • calgary, alberta
Posted Jul 17 2017, 22:58

Ok, we are up to post 9, I am just about to begin some real construction work now.  I have to gloss over a lot of detail work to get this material up, I havent touched on the hours of details, plans, permits, etc.  back to the build with post 9.

post 9 - active site management

The benefit of having an aware, motivated, and empowered manager on site during key moments of construction cannot be overstated. My definition of an active site manager, is someone who knows what needs to be done, is empowered to react to opportunities, and is rewarded from best practices.

On my sites, this person, being me, is supremely aware of how easily mistakes happen and how costly these mistakes can be. Maintaining a state of eternal readiness to act, while mentally tiring, can lead to major unexpected site savings, as today's case study will describe.

No More Sewer Lift Stations

Having identified the job site as a shallow service location, we budgeted an additional $2500, plus significant inconvenience factor for install of sewer lift stations. What this means is the basement floor is lower than the City sewer main, so cannot drain by gravity. The basement level, usually having a wet bar, bathroom and furnace floor drain can generate substantial waste water, this must be contained in a large sump basin, and pumped upward into the City sewer main. Over time this a possible maintenance and failure point, wastes space, makes noise, needs professional plumbing skills to have done properly and costs a lot of money. There is not a single beneficial feature of the sewer lift station compared to standard gravity drainage.

However, once our crew dug up the street and compared the height of the City sewer main to our surveyed top of footing mark, it became clear that, with standard slope, we could slide the sewer pipe just under our footing. This is where having the boss on site made the difference. The contractor was hired to bring the sewer lines just to the edge of the excavation and cap them there. The sewer would be brought into the house by coring a four inch hole through the concrete wall of the basement (which does not yet exist) where it would then be connected much later by the plumber to the lift station. Having identified the potential to bring the sewer lines into the building itself, I was able to get the contractor to add a length of pipe to each of the drain lines by trenching through the hard ground of the bottom of our excavation, and then bed the pipes in a scoop of gravel. All this material and machinery was on site, for no extra cost.

In a more passively managed project, the absentee builder would have hired the crew to do the service work and showed up after the job was complete to pay the bill. At this point the opportunity to extend the sewer beneath the footing would have been lost. The builder would have spent little to no time on actually managing the project (this is what builders like) and the cost would have been to the client of a $2500 expense plus having to live permanently without gravity drainage of the basement plumbing, and future maintenance liability. Passive management is how inner city construction tends to happen. This is because the investment side of the building company is detached (does not attend sites often) from the site management staff. The link between a motivated and rewarded site manager is lost as soon as the site manager is not in an ownership position. In a passively managed build, the owner would not have been aware of the significant site saving opportunity that presented itself for just a brief (2-3 hour) window that could only have been capitalized on by an aware manager empowered to make an instant decision.

Our next blog post will show the actual service installation and describe some of the cost involved for the typical inner city project.

post 10 - inner city sewer install

Sewer install is quite literally one of the most important features of a new home and should be a great comfort to the new owner than they will be getting a brand new system connected to an existing 50-70 year old piece of City infrastructure. A terrifying mess will be a guaranteed outcome if this work is done poorly.

Due to the sensitive nature of the work, involving shutting down streets and digging up the City owned roads and sidewalks, only indemnified contractors can do this work. The work is a real technical specialty, and the handful of indemnified crews have all the big toys to go along with this massive and time sensitive undertaking.

This brand new excavator was recently purchased by the owners at XXXXXXX Underground, at a cost of $190,000. This purchase was motivated by the failed $10,000 turbo unit in the old machine, and the pressure to install 170 sewer systems per season means down time is not acceptable.

In addition to the costly gear, the indemnified crews have a certain amount of pricing power over any client that needs the work done. During a 'boom' year, expect to pay a significant premium for this work. We have had the pleasure of hiring Precision Underground Services for the last few jobs we have done, one of the best indemnified crews doing this work in Canada.

To complete the job, a significant amount of work needs to be done in advance by the builder. This all comes at great cost as you will soon see.

1. Get a grade slip and hire the crew - the grade slip is provided once a DP is submitted to the city. The grade slip provides the information that is used to quote the job (depth of sewer). You can do some advance scouting here but basically you are at the mercy here of what the grade slip says. The job can be quoted now, this time we did not bother getting multiple bids (will explain why later).

2. Pay the asphalt degradation fee - this will cost between $1900 and $6000. We got off lucky this time because we are digging in an old road that hasn't been repaved recently. Our next job we are not so lucky...

3. Pay the $4250 water shutoff fee. This is the good news, you can get this back by doing the service kill, (which we have now done today - great for us to get that deposit back because we have another to pay soon).

4. Demolish the site and dig the basement. Pouring the basement and building the house may be necessary here if the indemnified crew can't get to you right away (often these crews have a multi month backlog).

5. We chose to go ahead with the install before pouring our basement because the winter season is upon us and sewer work largely shuts down. Cutting through frost is very difficult as well as properly repairing the road. This proved to be extremely beneficial. By opening up the street we found that the sewer was just deep enough to allow us to gravity drain the basement plumbing, saving $2500 plus major aggravation on site. Using the standard technique, the sewer would have been stubbed out to the property line and connected later, and lack of detailed measurements would have necessitated a higher pipe and lift stations.

6. Work is done following a similar methodology which is shown in the photos below

dig up the street and kill the old service for the sanitary water. This was being done as we arrived to the job site. Fortunately this crew starts work while builders are still in bed

Next the street is trenched for the new water lines to be run to the basement of the house. The lines are 1 inch pex pipe and must be 2.3 M deep to avoid frost issue.

Note the shoring boards are used to prevent cave ins while trenching. The crew has a genius system where the bracing pipes are charged with compressed air and quickly create a safe work zone. the lower of the two braces is removed once a bed of gravel is laid to bed the new lines.

Once the trench is prepared the water lines go in.

The vertical pipes show the water shutoff valves. These are barely visible at the back of the frame.

More gravel is added and the sewer pipes are laid according to the proper slope of 3 inch per length of pipe

At this point the City inspector will be called to make sure the work is going according to the many rules of how this job must be done. Not surprisingly, the work is passed quickly.

The trench can be partly backfilled at this point. The trench must be compacted as it is filled, and of course the best tool for the job is the 'hoe pack'. The machine is so powerful the reverberations of the tool can be felt much like an earthquake for a wide area around the operator. The machine is also able to span the trench to allow it to fill the trench and compact it quickly. The operator is highly skilled and crosses the trench repeatedly and can change tools at the end of the arm of the machine - hands free

This excavator must carefully expose the City water and sewer mains, not damage them while doing so, and remove enough material that the remainder is easily hand dug. The work is efficiently staged such that one pipe is being exposed while the other is being covered. All of this is happening in a manner that makes it look easy, but we are pretty confidant this is not at all easy, particularly in the way it is done and the pace of completion.

At the far end of the trench the water lines, already bedded in much of the trench, are connected using a wet connect tap to the City main, that remains pressurized at all times.

This tool is used to tap into the City water main. After connecting the water lines, the service is now completely live, and can be covered.

This has been a brief overview of the install process. There is much more detail to go over but this post is lengthy enough already. This is about the least DIY friendly activity in construction today, but the site manager still has a role to play in making sure the work is done well and the outcome is what was agreed to in the contract. The last role of the site manager is to hand over payment for the work. The job tends to cost between $15,000 and $30,000 depending on the site condition and complexity of the install. We got off pretty easy this time with a bill well under the $20,000 level. Thanks again to XXXX Underground for the fine job 

post 11 - basement development 

Developing an inner city basement has a number of elements that must be carefully orchestrated into the finished product;

  • the hole has to get dug in the right spot, so the surveyor is essential before work begins
  • the excavator must get the hole level and at the proper depth at the bottom of the footing
  • the engineer must take the sample for soil bearing and sulphate content of the soil, this will impact concrete selection later (the mix is variable depending on the project requirements)
  • the engineer must already have developed plans for the footing rebar detail and thickness, and wall rebar pattern. This is variable based on soil bearing, depth of backfill, and the weight of the structure above
  • the lumber yard supplies the package necessary for the work, usually lumber, stakes, weeping tile and rebar
  • the cribbing crew sets the footing forms in place
  • concrete placing crew, pump truck and mix trucks are now called upon to pour the footing
  • the cribbing crew arrives back on site to set the forms and rebar
  • the engineer usually requires a site visit at this point to inspect the foundation wall detail
  • the same concrete placing crew returns to pour the basement
  • a form stripping crew is usually brought in to peel off the forms and load the trailer
  • waterproofing is applied to the basement walls
  • gravel and weeping tile is delivered to site and installed
  • the city is called in for a pre-back fill inspection
  • the excavator returns to backfill the basement
  • to add another step, at some point the sewer and water lines can be brought in, in our opinion the sooner the better for this specialized task.

Our semi detached project is currently midway through the process, with the footing having been poured today. Let's hope our cribbing crew can get the walls up right away. Here are some photos of the footing stage of the basement project with captions to provide further detail on what is happening.

post 12 - cribbing

The crew started yesterday cribbing the basement walls. They put the insides up first, pass ties through the slits in the boards, and build a wood box around the top called the ladders.

A series of rows of rebar are added to the walls, then the outside walls are raised. Finally vertical rebar is added and the walls are braced for the pour.

This is a fast and hardworking crew. They can get a basement set up in a day or two. They ordered the pour already and the engineer has stopped by to give his ok. We will visit the site later today and take a few shots of the cribbing. Here is a view from yesterday afternoon.  

Our cribbers finished the job quickly and were already finished by lunch, as they are racing the weather and trying to get another couple jobs done. Our project engineer arrived to site at 8:30 in the morning and had the inspection complete, giving the go ahead for pouring later that afternoon.

We will show a series of photos below describing the final stages of the cribbing project. Note that we were able to get our pour done in above freezing conditions. The sand and water components of the mix are heated at the plant, so the mix arrives able to set up properly in cooler weather. There is a large cost to the winter heat included in the price of the concrete, but it is worth the investment ensure a good pour.

This week activity has been constant on site. We went from basically an empty, surveyed hole in the ground to having the sewer installed, the basement cribbed, inspected and poured, and tomorrow we will have the forms stripped and the walls damp proofed. During the week we also successfully applied for a demolition permit for our next project, set up all the service disconnets so the house can be demolished, arranged an asbestos test for the weekend, reviewed the plans for our three unit townhouse and sent feedback to the design team, and salvaged/sold some appliances from the old house on site. We also arranged a deal to swap out our construction truck for a new model, trained a novice builder friend how to get a demolition permit for his first project, and attended parent teacher interviews for both kids. We spent a significant portion of our construction budget, approximately $40,000 of invoices will be paid based on the work week. We will provide an update on expenditures to date in a future post. That is all for now.

From strippers are some of the hardest working and most under appreciated labourers in the construction business today. Of all the unpleasantness that goes into building a house, form stripping is among the nastiest, hardest, most repetitive and overall toughest jobs a person can have.

A typical suburban bred, desk dwelling softie would be unlikely to survive a single shift of form stripping. For this reason alone, we should salute the form strippers, without them the foundation business would not be the efficient machine it is today. Keep in mind we started from an empty hole in the ground on tuesday, and by saturday all the forms were peeled off and stacked back on the trailer.

The job is remarkably simple. Strip the bracing and forms off a newly poured basement, haul the heavy, moisture laden, filthy 9 ft sheets of plywood out of the excavated area up a slippery ramp and drop on the trailer. Do this 100 more times inside and out of the basement and the job is done. Drive on to the next basement and do it all over again. Thanks again form strippers for getting our basement done on a saturday morning. Here is a series of photos showing the essence of form stripping

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