Removing
a Bearing Wall:
You may want to remove a bearing
wall...or at least, you think that it's a bearing wall. Don't
assume that just because the wall studs seem a bit loose, or
because the joists above the wall are continuous across the
top of the wall, that the wall is not "load-bearing". We often
find that older homes were constructed with continuous joists
across the width of the house, yet the floor joist relies upon
the extra support that it gets from the wall and supporting
floor joists below. Remember, even if the floor above does not
fall down after you remove a wall, you may be creating an over-spanned
floor condition which is potentially unsafe !
We can usually determine
whether or not a wall is load-bearing by making a site visit
to inspect. Sometimes, we may need to cut a small hole in the
ceiling so that we can confirm the size and direction of floor
framing. In some circumstances, we can make conservative (safe)
assumptions without cutting holes, however these assumptions
need to be verified by the Contractor during construction.
Most jobs like this involve
one site visit, and about 1 day of our work in the office to
draw-up a partial plan and specify the necessary beams and posts.
Design costs for these types of projects vary depending upon
the number of beams required and the complexity involved in
transferring loads from the end of new beams down to the foundations
below. Building permit fees for simple interior renovations
like this are quite inexpensive, sometimes less than $100.
Key
Issues Are:
When you remove a bearing wall,
a beam with support posts needs to be installed to replace
the bearing wall. Electrical, Heating, and Plumbing services
may be inside the wall, and these components need to be considered
in the context of the renovation.
Beam may be "dropped"
below the ceiling, or "flush" mounted, so that it is hidden.
It is less expensive to supply and install a dropped beam.
For a wood beam, the approximate depth of the beam will be
equal to the span length divided by about 17. For a steel
beam, the approximate depth of the beam will be equal to the
span length divided by about 24. ( This is only a guideline
that you can use for planning purposes and should not be relied
upon to replace competent engineering design. )
Posts at the end of the
new beam need to be supported properly. Typically, we look
for support from a beam in the floor below, or we try to arrange
for posts to be supported on masonry or concrete walls from
below. Sometimes, considerable additional work is needed to
provide the proper support for the new posts, and this work
can add considerable cost to your project. Failure to provide
proper support posts can lead to serious consequences, even
collapse of the floor above.
We strongly advise you
to have an engineer design your beam and posts, and to get
a building permit prior to commencing construction.
Underpinning
& Benching ?
If you are planning to lower
your basement floor, then you will require a building permit,
and almost undoubtedly, the Municipality will require that
you retain a Structural Engineer to prepare drawings for you.
There are two common
methods by which the basement floor of your home can be lowered:
1. Underpinning
the
foundation walls: In this method, a sequence of holes
are dug-out from under the footing of your home. ( The footing
is the concrete or brick pad which spreads the load of the
foundation walls onto the soil. ) Typically, a series of
4' wide holes, separated by 8' of undisturbed soil, is prepared
and filled with concrete. The top 2" of the concrete filled
hole is packed with non-shrink grout, rather than filled
to the top with concrete, so as to avoid the possibility
that air pockets are present. Once the first series of holes
are filled with concrete, the adjacent 4' wide segment is
dug-out, and the underpinning process continues. Here, the
idea is that you extend the footing of the house to a lower
level, which then permits you to dig-out the soil from the
inside of the basement, without undermining the foundation
walls of the house. The process is very labour intensive,
and quite costly.
2. Benching:
In this method, a stable soil slope is maintained between
the lowered basement floor level, and the underside of the
original footings (to avoid undermining the footings). Then,
a steel reinforced concrete "bench" is poured over top of
the stable soil slope, to ensure that the soil slope is
protected. This process is less expensive, however it leaves
you with a concrete bench around the interior perimeter
of the basement.
The municipality is also
very likely going to ask you to have your engineer carry out
periodic inspections of the underpinning operations, and to
provide the municipality with Site Inspection Reports which
confirm that the underpinning work is being carried out in
accordance with the design.
Make sure that you check
the level of the sanitary sewer connection before starting
this type of work. If the sewer is higher than your basement
floor, then you may have to install a sanitary ejector pump
in the basement at an additional cost.
Make sure that underpinning
of your foundation walls does not undermine your neighbors
footings. This is quite possible if your home is very close
to your neighbors house. If you accidentally undermine your
neighbors footings, then you may need to underpin their footings
as well to ensure the stability of your neighbors house.
Finally, make sure that
the water table is not so high that your new basement floor
is "underwater". You should also make sure that the water
table is at least about 24" below the level of your new underpinned
wall, since soil bearing capacities must be reduced when the
water table is near the surface.
Do
you need a building permit ? (
probably if you're checking this website ! )
If you are carrying out a construction
project on your home, you probably need a building permit. Undoubtedly
you will need a building permit if you are making an addition
to you home, or if you are making any changes to walls or partitions.
It is best to call your municipality to find out if you need
a permit. For the City of Toronto, go to http://www.toronto.ca/building/building_permits.htm
Many people don't want
to apply for a building permit because of the time and cost
associated with the approval process. However, you may be surprised
that many small renovations can be carried out under a Fast-Track
permit, which can be obtained on the same day that you make
the application.
We strongly recommend that
you get a building permit for your renovation, for the following
very good reasons:
1.
It ensures that plans for the project have been clearly documented.
In order to build anything, it
is best to prepare some kind of plans in advance of construction.
By going through the motions of preparing drawings for the project,
unforeseen problems can be avoided, and a clear picture of the
overall scope of the project is defined. Most people need drawings
to help define what it is that they want to achieve. By having
clear construction documents, you can get true "apples-to-apples"
prices from different Contractors for the same scope of work.
2.
It helps to ensure that the project conforms to minimum standards
Before a municipality grants
a building permit, they usually want to check over the plans
for compliance with the Building Codes and Zoning by-laws. Sometimes,
the municipality puts most of the code compliance onus onto
the design professionals that prepared the plans for the project.
This is no trivial matter, since very significant liability
is attributed to design professionals and municipalities when
a building permit is issued.
3.
The municipality will "checkup" on your construction work as
it progresses
As part of the building
permit process, most municipalities will send inspectors out
to check that work is proceeding in accordance with the approved
permit plans. These inspections normally visit at key stages
during construction, and the site inspections are intended to
ensure that the construction work conforms to the approved permit
plans. Regular inspections keep the Contractor's honest and
on-their-toes, and serves as an independent check that work
is being carried out properly.
4.
It's the Law:
In most cases, you are
required by law to obtain a building permit for your project
prior to construction. If you renovate your house without a
building permit, then you could be held liable to all future
owners of the house for creating hidden defects in the building
structure. Even worse, you could be required to tear-down your
renovation in the event that your construction work does not
comply with the building code or with zoning by-laws which may
apply to your home.
It is best to check with your
municipality to see if you need a building permit for your renovation,
however if your project requires the removal of any walls or
other elements which may be of a structural nature, it is likely
that your municipality will require you to get a permit. Try
calling your municipality and ask to speak to someone about
requirements for building permits. Most municipalities are very
helpful in this regard. ( Don't be afraid of the Building Department
- they are there to help. )
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Do
you need an Engineer for a Building Permit application:
You may be frustrated because
your building permit application has been rejected and you have
been told that you need an engineer to review and stamp your
drawings. A municipality is entitled to demand that an engineer
be retained to review and approve the construction documents
when a project ( or a part thereof ) does not conform to all
of the requirement and limitations of Part 9 of the Ontario
Building Code.
Many house designers don't know
exactly when they need an engineer, and more and more home designers
are hiring engineers to specify the "structural" parts of their
designs. By doing so, the designer is relieved of the structural
engineering "liability", and the Owner can rest assured that
the structural design is correct. Often, Designers and Architects
ask the Owner to hire structural engineering services directly
so that the designer is "out-of-the-loop" of liability for this
part of the design.
Of course, Part 9 of the Ontario
Building Code is the part which applies to Housing and Small
Buildings, and this part of the Code is written so that individuals
without explicit technical training in Architecture or Engineering
can design and construct buildings without having to engage
the services of an Architect or Engineering professional. Your
drawings may have been prepared by an Architectural Technologist,
an Interior Designer, or a Design-Build Contractor, all of which
may be well qualified to design the structure of your home in
accordance with Part 9 of the Ontario Building Code.
A building which complies with
all parts of Part 9 does not need to be designed by either an
architect or and engineer, and a municipal building department
can issue building permits for this type of construction. It
is only when parts of the project do not conform to the limitations
of Part 9 that the municipality requires professional design
by an architect or an engineer.
As of January 1, 2006, Ontario's
new Bill 124 will come into effect, and this will mean that
most building permit applications which are made to a municipality
will need to be "stamped" by a "designer" who has passed certain
building code examinations. The new requirements are an attempt
to improve the quality of building permit submissions, and to
place much more responsibility on the shoulders of individual
building designers (who now will need to be insured). In return,
the public can expect building permit waiting times to drop
from an average of about 8 weeks, down to a legislated maximum
waiting period of 10 days !
The application of Part 9 to
buildings is generally limited to building which are 3 stories
or less, and have a building area (footprint) not exceeding
about 6460 square feet. However, even if your building conforms
to the above restrictions, there are many other parts of the
building which may not conform.
Common
examples of construction which may not conform to Part 9 include:
Designs with large open
areas - designs where clear spans
of floor systems exceed approximately 20 feet or about 6.0 m
commonly do not conform to Part 9 and require engineering to
ensure sufficient strength, or to ensure that floors are sufficiently
rigid and do not "bounce".
Designs which incorporate
vendor engineers products, such as Engineered floor joists
( commonly called I-Joists ) and engineered wood beams ( commonly
called LVL's, Microlam or PSL beams ).
Designs with basement foundation
walls which are more than 8'-2" high cannot be designed
with Part 9 and require engineering. It is currently popular
to have 9' ceilings in residential basements, and these types
of foundations cannot be designed with Part 9.
Designs which include few
or no interior walls and also incorporate large window openings
in the front, rear, or both. Homes such as this often require
steel portal frames to be designed to carry lateral wind or
seismic loads around window and door openings, even if they
are "shielded" from wind by adjacent houses.
Designs where exterior walls
exceed approximately 11' - 10" high without any lateral
support. This condition commonly occurs in exterior walls, beside
large stairway openings, where the stairway itself provides
no lateral support for the exterior wall.
Designs which are to be constructed
on soil which is incompetent ( typically where the soil
bearing capacity is less than 75kPa or 1500 psf ) Many builders
don't know when the soil is not sufficient to support the load
of the house until such time that a building inspector arrives
on site and stop's work. Unfortunately, many homes get constructed
on poor soil, which leads to foundation settlement, cracked
foundation walls, wet basements, etc.
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Need
an Engineer to Inspect ?
You may have identified
a crack in a foundation wall, or a sagging or uneven floor,
and you are concerned that there may be a serious problem. We
can make a site visit to try to evaluate the situation.
For
Existing Homes:
Cracked foundation walls,
cracked floor slabs, cracked exterior masonry, sagging floors,
uneven stairs, etc.
For
New Homes:
Poor soil conditions encountered
during excavation, and the building inspector needs an engineer
to certify that the soil bearing capacity is sufficient to carry
the weight of the building.
As-built construction deviates
from the approved permit plans and the inspector cannot certify
that the as-built condition is acceptable.
The contractor makes a mistake
and constructs part of the building in an incorrect or unconventional
manner, and the as-built condition needs to be assessed by a
professional engineer.
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Cracked
Walls:
If you have a cracked wall
in your house, you may be concerned that the crack is a symptom
of a serious structural problem. You may be reassured to know
that the vast majority of the cracks that we investigate are
not serious in nature, and very rarely indicate that there is
a serious problems with your home.
Cracks
in Foundation Walls are very common. In fact, almost
all concrete and masonry structures have some small vertical
cracks which are usually of little consequence. Concrete foundation
walls often develop some very narrow vertical cracks immediately
after construction ( less than 1mm wide ), due to shrinkage
of concrete shortly after pouring of the concrete. Long foundation
walls of houses (walls longer than about 50') will almost always
develop some minor shrinkage cracks after construction, especially
if your foundation walls are constructed with plain concrete
( concrete which is not reinforced with steel reinforcing bars
). If water is entering your basement through a small vertical
crack, you should take measures to seal the crack to eliminate
the water. Harmful molds can develop in a damp basement environment
which can be harmful to your health.
If the wall has cracked and the
wall has shifted vertically across the crack, then the crack
may be a settlement crack. Most settlement cracks are diagonal
cracks, and can be an indication of poor foundation construction,
or, poor soil conditions. Diagonal cracks can be a sign of a
serious underlying condition. In some cases, the soil which
is located below the foundations of your house can expand or
contract slightly, causing cracks in foundation walls.
If your foundation wall has horizontal
cracks, you should consult an engineer immediately since this
type of crack could reflect a serious deficiency in the foundation
wall.
Cracks
in Above-Grade Walls in older homes is very common, especially
those with plaster construction. Many older homes have undergone
thousands of cycles of changes from humid summer conditions
to dry winter conditions, which tend to cause underlying wood
frame construction or wood lath to expand and contract, leading
to deterioration of plaster finishes. Also, some older homes
may not have been constructed properly, resulting in over-spanned
floor joists and overspanned support beams. Many older homes
were built before building standards existed, and before municipal
building inspectors were around to ensure that homes were built
properly.
When we need to attend a site,
we charge a minimum fee for a site visit. Since residential
projects are typically very small and total fees are not large,
we cannot afford to offer free site consultations. Only in certain
special circumstances do we waive our minimum site visit fee.
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Sloping
Floors:
Sloping floors in any house
are generally not a good sign. Sloping floors likely indicate
one of the following conditions:
1. Settlement of the foundations
of the house have caused parts of the foundations to sink,
leading to sloping floors.
2. Improper floor framing:
If the floor "sags" in some areas, it is likely that floor
joists are overspanned, resulting in a sag in the floor system.
If the floor system is also "bouncy", then this is likely
the problem.
It is also possible that beams
which support areas of the floor are insufficient, or that
a bearing wall has been mistakenly removed during a prior
renovation. A sagging floor could be due to inadequate structural
support of an otherwise perfectly good floor system.
In some circumstances, sloping
floors may indicate that part of the floor framing system
has failed, however the floor has not collapsed due to some
redundancy in the structural framing system. We often see
second floor systems "sagging" around openings to 2nd floor
stairways, where the stairway opening has been framed by simply
doubling-up floor joists to form header and trimmer joists.
Engineering analysis often reveals that trimmers need to be
tripled or quadrupled, yet common practice is to simply use
double-joists, which leads to skewed stairways and sagging
floors over time.
Fixing
a Sloping Floor:
Before spending considerable
time and money trying to fix a sloping floor, you should consult
a structural engineer to identify the cause of the problem.
For example, if foundation settlement is the problem, then you
may need to carry out remedial measures to prevent further settlement.
Often people think that the settlement has " finished ", since
the house is old. However, this is an incorrect assumption to
make. Soils take hundreds of years to consolidate after they
have been disturbed. While it is possible that future settlement
will not be large, it is almost impossible to count-on. It would
not be wise to invest thousands of dollars into a renovation,
only later to find additional settlement cracks taking place.
In our experience, where settlement has taken place, it is very
likely that settlement will continue to take place for many
years, unless some very direct and tangible measures are taken
to curtail the settlement once and for all.
Once you have fixed the sloping
floor, you may be able to correct the sloping floor surface
by building-up a new subfloor over top of the existing sloping
floor. 2"x4" sleepers which are "ripped" at an angle can be
installed over top of the sloping floor joists, and a new subfloor
installed on the the new surface.
Another way of fixing an uneven
floor is to install a self-levelling cementitious grout, such
as Maxxon's Gypcrete, and then, install a new subfloor on the
new level surface. If you are considering this option, make
sure that your existing floor system can safely support the
increased loads.
Whenever floor leveling renovations
are contemplated, you will need to maintain or modify the level
of the top of the stairs, adjust the level of baseboards, window
and door frames, install new finished floors, etc.
You should carefully consider
the hidden liabilities which are contained within a home with
sloping floors, since repairing a home with sloping floors can
be very costly.
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Site
Visit:
When we need to attend
a site, one of our staff will come out and meet with you to
discuss the matter at hand. Typically, we visit for no more
than about 1 hour on site ( except when we need to take detailed
measurements ). Our initial site visit is primarily a consultation
to discuss structural engineering matters that affect the project.
During our site visit, we may suggest ways to approach a problem
or a situation, suggest possible methods by which a solution
may be attained, etc. However, our initial site visit is a general
consultation only, with no specific technical design recommendations
to be given in our report.
Typically, our initial site visit
includes a report which describes the structural situation,
and recommends a general approach which may be suitable to solve
the problem at hand. Our recommendations may be that we need
to be retained to design certain remedial measures, or we may
recommend that further investigation be carried out by us, or
by another specialty consultant.
When we need to attend a site,
we charge a minimum fee for a site visit. Since residential
projects are typically very small and total fees are not large,
we cannot afford to offer free site consultations. Only in certain
special circumstances do we waive our minimum site visit fee.
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Our
Fees:
The cost of having
us provide structural engineering services for your project varies
depending upon the complexity and size of your project. Residential
projects are difficult to estimate without us first being able
to review, in some detail, the amount of work which will be involved.
If you don't already
have some plans drawn-up for the job, it is likely necessary for
us to visit the house, and discuss the project with you. Since
residential project fees are generally small, we cannot afford
to provide you with free site consultations - we charge our site
visit fee for this service.
However, if you have
plans for the project which depict the scope-of-work, you or your
designer can send us drawings, and we can give you a fee proposal
based upon that scope of work. We do not charge for this type
of proposal.
There are two approaches
to delivering our services:
1. We "markup" design
drawings provided to us with the required structural information,
and then your designer incorporates this information into the
design drawings. We stamp the final drawings for "structural content
only" prior to your making your building permit submission.
2. We prepare separate
structural drawings and specifications for your project. Here,
we receive final CAD drawings of your project, and we prepare
separate structural drawings. Our structural drawings are stamped
prior to delivering you the final drawings.
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Delivery
Time:
Since most of
our projects are small, we rarely have a large backlog of projects.
Typical turnaround time is about 3 weeks. In some circumstances,
we can deliver projects faster.
Please feel free to
contact us by e-mail or phone at 416 - 489 -
1228 x 221. For phone messages, it may take up to 48h for us to
return you call. Please be patient, but feel free to nag us.
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