HOW TO BUILD A DRY BASEMENT & MAIN FLOOR
THINGS TO DO TO KEEP A BASEMENT DRY
GET RID OF WATER COMING FROM ALL SIDES
PUNCTURING FOUNDATION WITHOUT LETTING WATER IN
VULNERABLE AREAS IN BUILDING ENVELOP
Lt LINTEL FLASHING & Tw THROUGH WALL FLASHING
DOUBLE-LAYERED CATHEDRAL ROOF CONSTRUCTION
FOUNDATION UPTURN DETAIL & SQUASH BLOCK FRAMING
EXTERNAL DETAILING ESSENTIALS & SOFFIT STRIP VENTING
INFOGRAPHICS DOUBLE REINFORCED CONCRETE FOUNDATION
INFOGRAPHICS ROOFING NOTES
DEEP JOISTS WITH CUTOUTS FOR LARGE DUCTS
INFOGRAPHICS INSULATED BRICK CHIMNEY IN ATTIC SPACE
infographic showing proper framing procedure to include air space behind exterior stucco finish
FRAMING FOR AIR SPACE BEHIND EXTERIOR STUCCO FINISH

Issues In Custom Homes 

Why Construction Management ?

Rather than selling a product, a packaged service or a promise, we offer our quarter-century of experience, our expertise, our knowledge and our accumulated wisdom to ensure the highest quality of custom homes are created for our clients.  True luxury in a house, contrary to popular belief, is narrowly defined.  Choosing materials that will last a century or more, building the structures to ensure extraordinarily strong and sturdy floors, roofs and walls, exceptionally high volume of space, ultra quiet floors, no randomly dropped ceilings, huge spans and column-free rooms, large expenses of glazed walls and doors, purpose-built components, the most up-to-date room shapes and proportions (yes, they do change with the times) and down to the single innocuous need of having just one step at the front entrance - are all part of the realm of custom luxury construction.  And more recently, the need for idiot-proof maintenance, passive-solar designs, energy-efficient designs and on-demand heating, cooling, hot water and ventilation are within the program.  But let's deal with the first thing first.

The Fear Of Black Mold

The only way to rule out black mold is to take away the environment in which it can thrive in. Moist, damp and cyclically wet-dry absorbent materials are ideal culture medium for growing black mold. Water gets in the house through the ground, the walls, the roofs, openings, gaps and cracks. Shrinkage and settlement are unavoidable. So surfaces do open up. To know how water gets in is half the battle. Moisture is created when humid warm air cools down and droplets of water are formed. Moisture is also formed when water evaporates into the air. We will deal with the vulnerable areas one by one where water or moisture can cause damage to the house.

At Grade & Underground Water Problems

At least on one side of your lot, your neighbor’s water is running towards your house. Never leave the grading of your yards to your landscaper or gardener. Do not plant trees within thirty feet of your house. Do not plant shrubs or plants within three feet of your house. Allow that three feet of ground for drainage and water run-off. Drainage channels should ideally take the place of eavestroughs. Some houses are too high or the lots too narrow for routine maintenance of the troughs. Nine out of ten houses that we have renovated never had their troughs cleaned out. And the water damage to the houses was horrific. For luxury homes with one, two or three steps at the front entrance, the main floor is basically below grade. Waterproof the upturned top of foundation properly to ensure water does not get inside the floor joists. We always completely waterproof our basements which are usually quite deep. The much more economical damp-proofing just does not make the grade. Imagine the water table as a body of water under your basement that is always there but can change shape and location. Spring in Toronto is wet and the greatest deluge of rain occurs in November. Expect the water table to be the highest in those months. Before designing your house, get a soil test done which will tell you how deep the water table is at the time of the core-drilling. It will also tell you what bearing capacity your soil has so that the engineer can size the footings and foundation accordingly. Water will always try to get into your basement. The sump pump is there to get rid of any water that tries. Also make sure a backflow prevention valve is installed where the main drain comes inside the house. A deep basement comes with other issues such as excavation cave in, high water table, need of a sewer pump for basement bathrooms, extra strength in foundation structure and access to deep services and utilities.

Pipes Going Through the Foundation

The foundation is full of holes, mostly holes drilled after the site is backfilled. For example, natural gas line needs to go through the foundation, so do the main drain and water lines, underground power lines, snow-melting tubes and conduits, sprinkler pipe, exhausts, vents and air intakes from basement rooms, air-conditioner coolant lines and landscape lighting, surveillance and external power lines. If the holes are drilled after backfill, water will get inside the house. Organize the holes in window wells and utility wells. Access will be much easier and water leaks will not be a problem. Install sleeves in the concrete forms before pouring the concrete. This needs planning ahead of time. Note that we even install a sleeve under the form of the footing so that the connection from the weeping tiles to the sump pump can be made after the foundation is poured.

Clear Stone Backfill

If stone slabs are to be installed around the building, make sure the backfill is clear stone properly compacted and not just soil. Note that to compact soil properly will take a great deal of force which will damage the foundation. If not properly compacted, the grade will sink and costly stone installation will settle and crack. With clear stone backfill, drainage is guaranteed and with the proper compaction and sloping, settlement will be minimal and water will run away from the house.

Why So Many Areas Prone to Water Entry

Water doesn’t just run downhill. It also goes sideways and up. By surface tension, pumping action, capillary action, osmosis and diffusion, water basically can go anywhere it wants. So anywhere on the building surfaces where water can stand still for a moment, there is a chance for it to go inside the house. On the roof where snow and ice can accumulate, water has lots of chance to collect and stand still. Around door and window openings, water can traverse along the outlines of the opening and go inside, when the brick or stucco on the exterior of the building comes in contact with the structure of the building, water can run along these bridges and come inside and most of all, corners, valleys, ridges, constrictions, base of walls, etc. where water can gather, stand still or be driven upwards are places where leakage can occur. As good construction mangers, we know where to apply the right waterproofing to stop the water leakage. We build stuccoed walls with an air space behind just like a brick wall. The rain-screen principle actually works not just for brick and stone but for stucco, wood and metal.

Moisture Turns Into Ice

Masonry fireplace chimneys are notorious troublemakers. The term masonry fireplace is an oxymoron in today’s world. It doesn’t heat the house. The fire is ornamental. And it leaks cold air in the winter. The unseen threat is hidden in the attic or the upper floors where cold air trapped in the brick chimney cools the moist warm air in the house. Condensation soon form around the upper part of the chimney. This moisture in turn freezes and a great lump of ice is formed. When the weather warms up, the ice melts and you have a flood coming down the attic. In some cities, luxury custom homes without a real masonry fireplace do not sell. We take all the precautions necessary to prevent the chimney from icing up. Insulating and vapor-proofing the masonry chimney is one way of dealing with the issue. Suggesting a sealed metal fireplace as an alternative to the client is another solution to the problem.

Layered Roof Construction

Before the invention and the popular use of roof waterproofing such as Grace Ice and Water Shield, roofs got quite wet underneath the shingles. This problem is evident whenever we strip an old roof during renovation - the wood deck underneath is rotten in many places. To keep mold and fungus from growing underneath, the building code requires us to build in a layer of air space underneath the roofing so that the roof can ‘air out’ and hopefully dry out. With help from modern technology, roofs are much drier nowadays but the plywood roof deck still gets damp from the constant contact with water. Furthermore if the space underneath the roof is occupied space, you want to keep the room cool in the summer. This is hard to do with a cathedral ceiling. We build our roofs in two components, the insulated layer and the water-shedding layer. We build in a six to twelve inch continuously-vented air space between the two layers. The generous air space keeps the room cool in the summer. We also insulate our roofs to R50 to R60 value. Most importantly, a separate air-conditioning system is installed for the uppermost level, independent of the main system. A roof-mounted AC unit is one of the best features that a three-story house can have.

Custom Detailing For Custom Homes

We have written in the Design Build Section that Shop Drawings are a major feature of our Design Build Service. The construction of custom homes is taken seriously in the design phase. All our detailing ties back to the issues presented above and there is a solution to each problem. For luxury homes that are virtually barrier free, the one step outside the main entrance is a tall order. The single step combined with a high ceiling in the basement means a very deep excavation which has its own set of issues. The upturned top of foundation detail is what we typically build. The reinforcing of the concrete (to make sure the upturn does not snap off) and the meticulous waterproofing of the area ensure a sound and dry installation. This design allows a walk-out at-grade patio in the back of the house too. We typically also prepare our own shop drawings for the framing carpenters. Every blocking, additional stud, joist, rafter or extraordinary framing feature is highlighted. Working in conjunction with our structural engineers, we devise the best and strongest ways to frame a house with special architectural features and requirements. Using very deep floor joists is our trademark. We design to a floor deflection of L/480 or less. Floors for marble slabs require very minimal deflection. We usually specify floor joists from 18” to 24” deep. The deeper joists allow the passage of large ducts without having to drop them below ceilings where they are unwanted. The lack of bulkhead is another Po Ku Design Build trademark.

Whereas Details Are Not Just For Looks

Landscapers build garden walls with dead-level stone coping on top and no waterproofing. You see this throughout the world. The walls look good for a couple of years and water starts to get in from the top. Within ten years the walls disintegrate especially in our land of the freeze-thaw cycles. Stone wall coping must have a slope on top, sloping outwards and waterproofing underneath to protect the wall below. All protruding mouldings, doodads, sills, thresholds, etc. must be sloped on top to shed water away from the building. In fact no ‘flat’ surface should remain flat. Always build in a slope away from the building. This way costly carved stonework and marblework on the exterior of the building will remain intact for decades. For better protection, large projections should be waterproofed and covered on top with aluminum or lead-coated copper flashing.

Nobody Knows Construction Better

When it comes to construction techniques and building science, we are the experts.  This expertise is on offer to you, our client, for use in creating your ideal home.  When we manage the construction for you, we actually look after every minute aspect of building a house to the strictest and latest standards of the industry. All the technical information and graphics in these sections are prepared by our firm in house.

Proper Framing Procedure For Stucco

There are many backing materials on the market today that supposedly vent the back of the rigid foam installed for exterior stucco finishes.  We believe in our own system of properly framing the outer layer of sheathing to provide a 1-1/2" air space for positive air circulation and water drainage behind the stucco.

Traditional Building Craft Revival

We collaborate with little known traditional craftspeople to carry out the intricate work that is needed in our high-end luxury custom home building projects.  Please read our blog page : The Revival of Traditional Building Crafts.

Related Section : Sideyard Issues

Related Section : Flooding