F2 - Describe Backfilling - LT #7 Flashcards
The main advantage of early backfilling is that:
The main advantage of early backfilling is that:
Material is easier to stack on-site and access is better around the building.
Mechanical damage is damage caused by:
Physical impact from any source.
Before backfilling can start, what must be done?
1) Perimter drain system installed
2) Foundation Damp-proofing
3) Placement of underground services
What is the minimum time that concrete foundations should be cured before backfilling?
14 days minimum cure time for foundations.
What causes the interior of foundations to be wet?
1) Cracked foundation walls
2) Rusted-out form ties
3) Poorly draining backfill
A 10” or larger boulder resting against a foundation wall can cause the wall to crack because the rock causes:
Point load against the foundation wall
When backfilling against foundation walls, it is best to:
Start with the corners first(they’re generally stronger)
Slab-On-Grade need:
Uniformly Dense Base
Why is it good to let the backfill stay in place for a length of time before finishing the grade surface?
Backfill will settle naturally and then the surface can be final graded.
Backfilled areas are usually compacted wherever:
Concrete walks or driveways will be placed over them.
Typically what is installed on the foundation walls before backfilling begins?
Floor system for lateral support.
Form tie ends should be plugged or parged over with:
low slump concrete mix of three parts sand to one part cement.
Foundation walls using ICF require protection from:
Mechanical damage above grade and require damp-proofing membrane below grade.
Before drainage pipes are installed around the foundation, the foundation wall must be:
Damp-proofed with a thick layer of: Bitumen.
What is a drainage mat?
Material that will direct moisture or water toward the drainage pipe. A 3/4” thick drainage mat provides an open space for collecting moisture or water to collect.
What material is used for backfilling?
Native material is used for backfilling, but many problems can result if material is not free-draining or if it contains large rocks.
A good rule for draining against the building is
At least 1.8 meters away from the building.
Once landscaping is complete, there must be at least:
6” of foundation extending above the finished surface, depending on the cladding type.
Foundation walls can support big vertical loads but what need supporting them?
Floor framing and basement slab
Soils containing loam will settle how much?
Soil containing loam will settle A significant amount, allowance is made for settling.
Backfilling should be done in layers how much?
Backfill done no greater than lifts of 12”
Backfills must be compacted where there is:
sidewalk, step, or driveway to be supported by the backfill, compaction is needed
Compacting should be done:
Compacting should be no closer than 300 mm from the foundation walls. Watering may be needed if the material is dry.
PWF require special care when backfilling, lateral pressures cannot exceed:
Equivalent to a fluid pressure of 4.7 KPA per metre of depth unless Engineered
The material used for backfilling PWF should be:
Well-draining granular material (sandy gravel or gravel) that is free of rocks and boulders.
Impervious material is used to provide a cap on the backfill to try to keep the rainwater from:
Impervious material is used to provide a cap on the backfill to try to keep the rainwater from:
Entering the porous layer and adding to the drainage load
Finish grade must be sloped away from the building in all directions, if the lot is slipping what should be graded into the site:
Finish grade must be sloped away from the building in all directions, if the lot is slipping what should be graded into the site:
A swale should be graded into the site to direct the surface away from building.
Bedding sand is required to be:
Bedding sand is required to be 4 “ thick below piping after compaction. 6” over rock.
Interior backfill material must be a mineral soil with:
Interior backfill material must be a mineral soil with Good compaction properties. 6” lifts and compacted between lifts.
