Friday, February 24, 2012

About A House - Peat Bog

Not sure if it's a well known fact, but the Cambie area near Douglas Park is a land mine of peat bog and underground water tables for new builds and renos. Here's a short summary of where the peat bogs are in Vancouver.

The first time we realized the real implication of its significance, we were well into our design stage. Since we were on a high side of the Cambie dip and we weren't building a basement, we thought our lot should be okay. First off, the city requires a geotechnical report as part of our permit application for projects in peat bog area.

From March to May of 2011, with slight apprehension, we were waiting for the results from our geotechnical engineer of soil sample to confirm the subsurface condition of our lot.  Although we were pretty confident that our lot should be on dry ground, there is always a chance that it's on peat. As part of the investigation, a total of four 8 ft deep holes were drilled to extract soil samples for analysis. To our relief, our report came back clean with some relatively minor excavation and backfilling recommendations. The cost of construction will be impacted but we soon learned that it's no big deal compared to what it could have been.

During this time, there were a few other construction projects around the bottom of the Cambie dip that were slightly ahead of ours, right on top of the peat bog. One project had to excavate all the soil out of the entire foot print of the house to the depth of a very deep basement. At first we were thinking "Boy! That's a deep basement.". Then we watched with horror how it was heavily braced against both sides of the neighbouring homes and completely backfilled with gravel. The house is slab on grade!! Talk about pouring money into the ground!!

Then there is another project directly across from Douglas Park (some of the most prized lots in the hood), it has completely come to a standstill and it's filled with water. YIKES!! Here's a picture....



If we knew then what we know now, I wonder if we'd have bought our lot... Huummmmmm...

I think at the very least we would have gone to talk to the City of Vancouver, it's a treasure trove of information for the biggest investment of one's life.

About A House - Timeline Story 2

There really isn't anything exciting going on at the site for the past 6 weeks while the team works on the foundation. However, I was amazed at how much construction material goes into building the foundation and requires as much meticulous attention to details as framing. It's doesn't get enough credit because it's flat!

Jan 6:  House positioned, surveyed, backfilled and ready for foundation construction.


Week of Jan 9 to 13: much of the construction material for the foundation was delivered.



Week of Jan16: freezing, icy weather set back, no progress for the entire week. Wished we had taken a picture of its frozen state. Opportunity lost!

Week of Jan 23: work resumed to build the foundation frame but interrupted by a few of days of continuous downpour.

Week of Jan 30: An intense week of banging to build the wood frame around the perimeter.






Week of Feb 6: The wood frame for the foundation is complete, now all the steel rods need to be inserted into the gaps. These rebars will be set into the concrete.


Feb 10: Up to this point since Feb 1, we have had amazing sunny dry days as the team work furiously to catch up. Foundation framing passes both structural engineering and city.  Ready for concrete pour.



Feb 13: Concrete poured for the foundation walls and crawl space floor.

Concrete mixing is a pretty sophisticated process. It is mixed just before it's sent over for the pour and the recipe du jour depends on the weather on that particular day.  We had 2 different kinds of concrete applied, a high water resistance composite for the crawl space and a "normal" for our region for foundation application mix for the rest. A total of 3 drums worth of concrete poured for the crawl space and perimeter of the foundation.

The stuff you learn off the internet... "concrete is the most consumed material by us humans after food & water."  Here's a link for anyone truly into the specs of concrete, and I had always thought they're the same as the ones in an extremely heavy paper bag that you buy from the local hardware store!

Feb 14:  Need to wait 2 weeks for the concrete to completely set before the framing for the house can begin. Meanwhile, the boards are coming off the foundation.

Feb 23: Drain tiles are installed and passed inspection.

Feb 24: Pouring money into the ground! Back fill with sand up to the slab on grade level. This is necessary due to the softness of the soil in the Cambie area. 7 truckloads today and probably 5 more next week. Maybe we should hold a sand castle competition before we pour the final slab on grade!









Feb 28: 5 more truck load of sand for backfill. The sand is pounded down and smoothed out.





Mar 1: Installation of drainage into the sand pit, rebar & insulation prep for the slab, insulation



Mar 6: concrete pour of the slab of grade.



This marks the end of foundation work! We had some visitors overnight when we returned the next day!



Total time: 2 months

Cost of demolition: $32,000
Cost of house foundation: still waiting for invoices