• 1. Options for ADUs on Multi-family Lots

    Under current state law, there are two options for adding ADUs to multi-family properties:

    ●  Conversion of existing non-livable space.
    ●  Construction up to 2 new detached ADUs

  • 2. Conversion of existing non-livable space

    ● Non-livable space in a multi-family property most commonly includes garages, carports, basements, or storage rooms. Properties with such spaces may be feasible locations for ADUs in the following quantities:
    ● For properties with 2-7 units: 1 conversion ADU
    ● For properties with 8+ units: 1 conversion ADU for every 4 existing units

  • 3. Construction of up to 2 new detached ADUs

    ● Under this option, a multi-family property owner can build up to two freestanding ADUs on their lot as long as required setback, square footage, and height limits are met. These units are similar in look and feel to detached ADUs on single-family lots, but can be designed in a way to match the aesthetic of your property. This option is not always feasible on multi-family lots that do not have adequate open space, usually in the rear of the property.


    State law requires local jurisdictions to allow for property owners to do either one of these options, but it does not require them to allow for both concurrently. In many jurisdictions, however, you may do just that, combining both of these options to add both conversion ADUs and new detached ADUs. Our Adapt Feasibility study will help you identify the full set of options available on your property to help you maximize the number of units you may potentially add.



Adding an additional dwelling unit (A.D.U.) to a property represents one of the best opportunities available to increase net operating income and property value.

  • 1. Building Permit Application Requirements

    Building Permits are reviewed for compliance with:

    ● Ontario Building Code
    ● Hamilton's Zoning By-law
    ● Niagara Escarpment Commission and Conservation Authorities Regulations
    ● Other applicable provincial and municipal regulations

    The purpose of a Building Permit is to ensure that zoning requirements, fire and structural safety standards and other building standards are met.

  • 2. Project that require a building Permit


    ● guard/railing replacement or new installation
    ● fences for swimming pools (enclosures)
    ● tent(s) greater than 60 square metres
    ● any-sized deck (covered or uncovered) where it is attached to a building
    ● detached uncovered deck greater than 10 square metres and more than 200 mm above adjacent grade
    ● detached covered deck greater than 10 square metres
    ● detached deck (covered or uncovered) less than or equal to 10 square metres where it is adjacent to or associated with a door to the building and more than 600 mm above grade
    ● detached structure less than or equal to 10 square metres containing plumbing
    ● detached structure greater than 10 square metres (except where accessory to a detached house, semi-detached house or row house)
    ● detached accessory structure (shed, garage, gazebo, carport) greater than 15 square metres where accessory to a detached house, semi-detached house or row house
    ● additions (includes enclosing existing porch)
    ● waterproofing/damp proofing foundation walls
    ● replacing weeping tile
    ● repairs to structural members (i.e. subfloor, roof sheathing, beams, lintels, etc.)
    ● raising or lowering (underpinning) a house to provide a full basement
    ● replacing roofing or exterior cladding with a different material
    ● solar panels
    ● ramps or elevating devices
    ● replacing structures in same size same location


    ● interior alterations including finishing or partially finishing a basement or other spaces
    ● finishing existing non-finished space
    ● walkout basement
    ● replacement of interior railings/guards
    ● adding an accessory apartment (conversion)
    ● relocating rooms/creation of new rooms
    ● material alterations including installing or replacing drywall and insulation
    ● creating new door or window openings or increasing the size of openings
    ● relocating door or window openings
    ● adding or removing walls (non-load bearing and load bearing), beams and lintels
    ● backwater valve
    ● waterproofing/damp proofing foundation walls
    ● internal weeping tile system
    ● sump pump
    ● fire damage repair
    ● changing the use of a building (e.g. lodging house, bed and breakfast or changing any part of a building from one use to another)
    ● establishing a home occupation (please contact us for more information)


    ● new plumbing or relocating plumbing
    ● new septic systems, repair or replacement
    ● installation of water meter, water, sanitary and storm services to the property line (Single Family Dwellings only)


    ● wood stoves or fireplaces
    ● new or replacement of ductwork in an HVAC system
    ● installation of internal plumbing


    ● demolitions for structures 10 square metres or greater (except for accessory structures not more than 15 square metres, as noted)
    ● partial demolitions of buildings
    ● partial demolition of an attached structure

  • 3. Modern Design Structures
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Building Permit Drawings

Building Permit Drawings

A Building Permit legally authorizes you to start construction of a building project in accordance with approved drawings and specifications.

  • 1. Modelling

    The first step is to model the structure’s mechanical skeleton, including its foundations, columns, beams, frames, trusses, and other elements. The start point is the architectural model. An architectural model shows what the structure will look like in reality, but it is not suitable for calculations due to the high level of detailing. The architectural model needs to be stripped until only the load-bearing structure remains. The load-bearing structure will transfer the applied loads to the ground.

    Translating the load-bearing structure to a model ready for calculations is called schematization or creating the wireframe model, the mechanical model, or the plan of the model.

    Schematization is a very important step: it is essential that that the mechanical model can anticipate loads since it would be the basis for the whole process.

    The most used structural elements which can be included in the structural model are:

    ● Beams;

    ● Columns;

    ● Struts and ties;

    ● Slabs;

    ● Shear walls;

    ● Membranes.

    Furthermore, modelling involves determining the structure’s material, whether it would be “structural steel”, “reinforced or prestressed concrete”, “timber”, or any material. The choice depends mostly upon the economy and safety of a structure. A lot of structure consists of both steel, concrete, and timber elements.

    Modelling also involves assuming dimensions for each element which is the basis for self-weight computation for the load analysis. Estimating the member size includes what should be the element width, the depth or the thickness. Rules of thumb can be used for the choice of the initial dimensions.

    Another relevant aspect in the modelling consists of defining the internal and external boundary conditions of the members that make up the structure.

  • 2. Load analysis

    Next, the structural engineer must identify all possible loads that the structure may experience during its lifetime. Examples of loads on structures are:

    ● Dead loads, meaning the self-weight of the structure

    ● Live loads: occupancy of people in buildings, moving equipment, and the movement of cars on bridges;

    ● Wind loads: any horizontal, uplift or shear pressures or forces that the wind exerts on a building;

    ● Snow loads: only applicable for structures expected to receive snowfall;

    ● Earthquake loads: when the structure is in a seismic region;

    ● Earth pressure: to be applied for tunnels, retaining walls, cellars;

    ● Water and ice: for some structures such as bridges, offshore platforms, and coastal structures;

    ● Thermal loads: Unequal heating or cooling of parts of the structure create high stresses;

    ● Dynamic loads: for example, induced by machinery.

    So, depending on where your structure is, you must consider the various kinds of loads. The values of these loads can be identified using appropriate structural design codes and references.

    In real life, different loads act simultaneously with the structure. The combination of the various loads should be evaluated. For instance, a simultaneous action between dead load (weight of the structure) and live load (use of the building by people) can be a load combination. But also, dead loads and wind loads can be a combination. Finding which is the worst load combination for your structure is a part of the loads analysis process. Usually, structural engineering software will automatically create a set with all possible loads combinations.

  • 3. Structural analysis

    In this step, we perform the analysis on the structural members. The goal is to investigate how the structural model behaves with the different load combinations made. The analysis of a whole structure is also known as the global analysis.

    The results of the analysis include the internal forces diagrams (shear, bending moment, normal, torsion and stresses), reactions, deformations/ deflections produced by the different load combinations.



Structural design is the process of creating a safe and functional structure under any load that it may experience. During this process, the structural engineer will determine the structure's stability, strength, and stiffness (rigidity).

  • 1. Purpose

    Waterproofing is usually required by building codes for structures that are built at or below ground level. Waterproofing and drainage considerations are especially important in cases where ground water is likely to build up in the soil or where there is a high water table.

    Water in the soil causes hydrostatic pressure to be exerted underneath basement floors and walls. This hydrostatic pressure can force water in through cracks, which can cause major structural damage as well as mold, decay, and other moisture-related problems.

  • 2. Methods

    Several measures exist to prevent water from penetrating a basement foundation or to divert water that has penetrated a foundation:

    ● Interior wall and floor sealers
    ● Interior water drainage
    ● Exterior drainage
    ● Exterior waterproofing coatings
    ● Box type waterproofing
    ● Foundation crack injections.

  • 3. Causes of water seepage and leaks

    Water seepage in basement and crawl spaces usually occurs over long periods of time and can be caused by numerous factors.

    Concrete is one of the most commonly used materials in home construction. When pockets of air are not removed, or the mixture is not allowed to cure properly, the concrete can crack, which allows water to force its way through the wall.
    Foundations (footings) are horizontal pads that define the perimeter of foundation walls. When footings are too narrow or are not laid deep enough, they are susceptible to movement caused by soil erosion.

    Gutters and downspouts are used to catch rain water as it falls and to discharge it away from houses and buildings. When gutters are clogged or downspouts are broken, rainwater is absorbed by the soil near the foundation, increasing hydrostatic pressure.



Basement waterproofing involves techniques and materials used to prevent water from penetrating the basement of a house or a building. Waterproofing a basement that is below ground level can require the application of sealant materials, the installation of drains and sump pumps, and more.

  • 1. New construction

    This would be different than a renovation or rehabilitated property that may have many new features. A new construction property can require a different purchase contract than a standard resale home.

New Constructions

New Constructions

is a piece of real estate that has completely new improvement on the property.

Based on 13 reviews
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Adam SellorsAdam Sellors
00:54 25 Oct 23
My partner and I are converting our single family home into a duplex and we were lucky enough to come across Decc. Mike has been phenomenal throughout the permit process. We were a little stressed taking on this large project, but Mike has been amazing, guiding us through the trials and tribulations that arise when working on a home built in the 1800’s. He presented great ideas during his walk through, and designed two fabulous units, easily overcoming what we thought were going to be major permit issues. Further, Mike was able to put us in contact with a construction company (555 construction) that specialize in this type of conversion. We recommended Mike to some close friends, who also conveyed a very positive experience. Thank you Mike!!!!!!!
Vanessa MilichVanessa Milich
20:47 27 Sep 23
Very professional and knowledgeable. Work was completed on time with no surprises. I would highly recommend this company to everyone.
Chris FritchChris Fritch
14:46 11 Sep 23
I have now had the pleasure of working with Mike on a number of projects and I am absolutely thrilled to have found him. His professionalism, attention to detail and knowledge is unmatched in the industry.I have worked with many engineers in the past and Mike leagues above them. Can not recommend DECC INC. enough!
Craig BeckerCraig Becker
14:22 03 Sep 23
I have now had the pleasure of working with Mike a few times and picked his brain dozens more. Simply put there is levels to this kind of stuff and Mike is at the top of his game. His ability to adjust his message from talking to city staff to contractors to home owners is impressive and you feel like you have a true partner in your project. One of the most impressive aspects of working with DECC Inc. was their ability to deliver permit on the day of closing. There was zero downtime and the team was able to get right to work.Having worked with multiple engineers in the past, there is good and bad, Mike and DECC Inc. are the best.
Stuart FletcherStuart Fletcher
01:32 24 Aug 23
We felt Mike was very open and honest from beginning by to end. From drawings to permits, to putting together the team to help us. He came recommended from a friend and he did not disappoint. We would highly recommend!!!!
Michael MonsonMichael Monson
15:42 16 Aug 23
Mike and the team at DECC Inc. were an absolute pleasure to collaborate with. They were thorough, professional and provided the absolute highest quality of customer service from commencement to completion of the additional dwelling unit within my home. DECC Inc. essentially rescued me from a previously incompetent design firm and I cannot recommend their services highly enough. If I could rate 6 stars, I would.
fam ilyfam ily
18:58 20 Jul 23
I was referred to DECC Inc. to do drawings for my duplex conversion. Mike made the process easy and seamless with the various permit applications and submissions, along with drawings for my new property conversion. Great communication throughout the entire process, with updates along the way. We had our permits in hand the day our property closed, allowing us to start the conversion immediately with no time lost (time is money). Highly recommend Mike!