ENGINEERED SHORING DESIGN & PLANS FOR NEW HOMES

 We provide engineered stamp drawings for Shoring Design specifically for building infill custom housing where new custom build houses are constructed on underused lots interspersed among older existing properties in established urban neighborhoods in Ontario. Engineered Shoring Design is required to protect adjacent structures and foundations and shoring of the excavation must be completed prior to the start of forming of the footing for the new custom infill home. By preventing caving in during excavation for a new custom infill home shoring mitigates risk to abutting lots and reassures adjacent homeowners. 

A geotechnical Report is required at address concerns due to poor soil conditions and/or slope stability.

TYPE 1 SOIL

• Hard, very dense. You can only penetrate it with difficulty by using a small sharp object.
• Low natural moisture content, high degree of internal strength.
• No signs of water seepage.
• Need mechanical equipment to excavate it. 

When excavated, the sides of the trench will appear smooth and shiny and will remain vertical with no water released from the trench wall. If exposed to sunlight for several days, the walls will lose their shiny appearance but remain intact. If exposed to rain or wet weather, the soil may break down along the edges.

TYPE 2 SOIL

• Very stiff, dense. You can penetrate it with moderate difficulty by using a small sharp object but a pick can be driven in easily.
• Low to medium natural moisture content,
• medium degree of internal strength.
• Has a damp appearance after it’s excavated.

The sides of a trench will remain vertical forseveral hours. After that, exposure to air and sunlight will cause tension cracks to appear. The soil will begin cracking and splaying into the trench.

TYPE 3 SOIL

• Stiff to firm, compact to loose in consistency. May be backfill or previously excavated soil.
• Signs of surface cracking and water seepage.
• When dry, it may run easily into a well-defined conical pile.
• Low degree of internal strength.

When dry, the sides of the trench will not stand vertically and will cave in to a natural slope (45°). When wet, the soil will stand for a short period. However, it dries quickly and chunks or slabs will start to fall into the trench.

TYPE 4 SOIL

• Soft to very soft, very loose in consistency, very sensitive to vibration and motion.
• Any disturbance significantly reduces its natural strength.
• Runs or flows easily unless completely supported before excavation.
• Almost no internal strength.
• Wet or muddy.
• Exerts substantial fluid pressure on its supporting system.

The sides of the trench must be supported and contained in order to excavate to any significant depth.

 Consider the location of the existing old house that is being demolished in relation to neighbouring structures. Overhead Hydro lines, buildings, fences, underground utilities including natural gas, electricity, water, sanitary and storm sewers, available onsite space, and several other site-specific factors need to be taken into account when planning for the demolition of an existing old house to construct a new custom infill home.  

The Occupational Health and Safety Act, Regulation, and Code regulate the health and safety of workers on a construction site for an infill home. For example, the Occupational Health and Safety Act regulates excavation in relation to worker safety, including soil stabilization, and appropriate sloping of an excavation. Depending on the height of the basement, the Occupational Health and Safety Act may require shoring to accommodate the depth of the excavation.   If the custom infill home builder can not provide sloping or benching to meet the Occupational Health and Safety regulations for excavations and trenching as per the Ontario Regulation 213/91, an engineered shoring plan prior to excavation is required. 

The Ontario Building Code notes that excavations shall be undertaken in a manner to prevent damage to adjacent property, existing structures, utilities, roads, and sidewalks.  
Shoring holds the excavation open and support the structures directly abutting the lot line.

Where a foundation wall is located less than 3m (10ft) from a property line, a licensed professional engineer's involvement for the excavation and/or shoring design is required. An engineered shoring plan is required for infill housing projects where:
New foundation walls will be 1.8m (6ft) or less from an adjacent property line, or
Excavation will be within 1.2 m (4ft) of a property line.
Shoring systems are always required to be engineered regardless of location.

In urban neoghbourhoods there are often existing homes that are old and of low density.  Old houses become new opportunities to improve mature neighbourhoods, breathing new life into old low-density communities. However, the construction of custom infill homes to replace old homes creates a unique set of challenges. Construction of a custom infill home often requires access to a portion of an adjacent lot at some point in the construction process. Access is requested or negotiated with the adjacent owner as required. Where elements of the excavation and/or shoring system are proposed to extend beyond the property line (e.g., shoring tiebacks), these works must be agreed upon by the adjacent property owner(s) by way of an informed consent agreement.  A municipal consent agreement must be obtained for works on municipal property from Right of Way. Typically issues with neighbouring properties can be mitigated with proper communication from the beginning and throughout the construction process of an infill home. 

Excavation to facilitate the construction of an infill home can cause damage to adjacent properties if not properly performed. As part of the excavation process for an infill home, the property owner, designer, and builder must work together and consider adequate shoring installation methods to prevent damage to the adjacent private and public properties, with specific consideration to the following Ontario Building Code (OBC) requirement: 

ONTARIO BUILDING CODE
Division B, Article 9.12.1.4. Precautions During Excavation
(1) Every excavation shall be undertaken in such a manner to prevent damage to adjacent property, existing structures, utilities, roads, and sidewalks at all stages of construction.
(2) Material shall not be placed nor shall equipment be operated or placed in or adjacent to an excavation1 in a manner that may endanger the integrity of the excavation or its supports. 

Excavation means the space created by the removal of soil, rock, or fill for the purposes of construction.
Adjacent property includes landscaping, walkways, driveways, fences, etc.

Under the Ontario Building Code, an owner and/or contractor must ensure that all work complies with the Ontario Building Code and that all work undertaken to construct an infill home does not damage or create a hazard to adjacent buildings (for example damage to structural components of a building.) Where the stability of an adjoining building may be endangered by excavation, the Ontario Building Code requires that adequate underpinning, shoring, and bracing will be provided to prevent damage to, or movement of, any part of an adjoining building, and the creation of a hazard to the public. 

 Excavation of a basement with a ceiling height of 2.4m (8ft) for a custom infill home may be accommodated within a 1.2m (4ft) setback form the side lot line because the required slope can be achieved. However, a basement depth of 2.7m (9ft) would require shoring in order to be accommodated within a 1.2m (4ft) side setback with the required slope. It is the responsibility of the custom home builder to determine when shoring is required to satisfy the requirements of the Occupational Health and Safety Act. When shoring is required, the custom home builder must ensure shoring is designed by a professional engineer and installed by the stamped drawings. 

Movement of the shoring system is inevitable. Vertical movements will result from the vertical loads on the soldier piles resulting from the inclined tiebacks and inward horizontal movement will result from the earth and water pressures. The magnitude of this movement can be controlled by sound construction practices. The lateral and vertical movement of the shoring system must be monitored especially at locations in which settlement sensitive structures are present, to ensure that movements are kept within acceptable range.

  An Engineered  Shoring Plan is a set of stamped engineering drawings that show the detailed site-specific shoring design and specifications. 

Typical Types of Shoring are as follows:

• Soldier Pile and Lagging
• Caisson / Secant Wall with Tieback Anchors
• Pressure/Chemical Grouting
• Hydraulic Shoring
• Soil Nails & Shotcrete
• Pneumatic Shoring
• Sheet Piles
• Box Shoring

Compression elements like Rakers and Struts are erected inside the excavation. Tension elements like tiebacks and deadman anchors ere installed outside the excavation to provide anchorage against the lateral earth pressures.

Temporary excavations in Type 3 soil must be sloped back at an inclination of 1 horizontal to 1 vertical (H to V).

Excavations extending below the groundwater table would be classified as a Type 4 soil and temporary excavations will have to be sloped back at 3 horizontal to 1 vertical from the base of the excavation.

Raker footings should be designed in accordance with the design principals for shallow foundations subject to inclined loading. All raker footings should be located outside the zone of influence of the buried portion of soldier piles, and at a distance of no less than 1.5D from the piles, where D = Depth of penetration of the piles below the base of the excavation. No excavation

should be made within two footings widths of the raker footings, on the side opposite the rakers.

We require a site plan that
Identify the building to be demolished and the location of fencing required to protect the site and adjacent properties
Identify the area of excavation, the proposed depth of excavation, and the location of foundation walls for the new infill home
to prepare an engineered Shoring Plan.

Our licensed Professional Engineers prepare cost effective engineered shoring plans including detailed shoring design, engineering specifications and sequencing of activities.   

 Our fee for preparing a typical stamped engineered Shoring Plan for the demolition of an existing house and construction of a new infill house in Ontario is $1,295+ HST and upon the receipt of the foundation details of the proposed infill home, an Engineered Shoring Plan can be completed in 3 to 5 days. 

For Additional Information regarding an Engineered Shoring Plan please contact

• Miaoyi Xue, P.Eng,
• Joo Min Park, MEng, P.Eng.
• Saloni Khoja, B.Arch.
• Edgar Labuac, P.Eng
• Weiming Lin, B.Eng
• Rui Cong Xia, B.ASc (Civil)
• Yuen Yu Ng, B.S.Sc (Arch)
• Hoi Ching So, B.S.Sc (Arch)
• Liu Sun, B.Des (Arch)

LAND & BUILDING EXPERTS

Land Line: 416 332 1743

After Hours / Text Messages: 416 727 8336

Email: landbuildex@gmail.com 

Our well experienced, qualified professional engineers licensed in the Province of Ontario, specializing in Shoring Design prepare Engineered Shoring  Plans to support to obtain infill building permits in Ontario including City of Toronto, Durham Region, Halton Region, Peel Region, York Region, Hamilton (City of Hamilton), Oshawa (City of Oshawa), Pickering (City of Pickering), Clarington (Municipality of Clarington), Ajax (Town of Ajax), Whitby (Town of Whitby), Brock (Township of Brock), Scugog (Township of Scugog), Uxbridge (Township of Uxbridge), Burlington (City of Burlington), Halton Hills (Town of Halton Hills), Milton (Town of Milton), Oakville (Town of Oakville), Brampton (City of Brampton), Mississauga (City of Mississauga), Caledon (Town of Caledon), Vaughan (City of Vaughan), Aurora (Town of Aurora), East Gwillimbury (Town of East Gwillimbury), Georgina (Town of Georgina), Markham (City of Markham), Newmarket (Town of Newmarket), Richmond Hill (City of Richmond Hill), Whitchurch-Stouffville (Town of Whitchurch-Stouffville), Bradford West Gwillimbury (Town of Bradford-West Gwillimbury), King (Township of King).