Basement Home Additions – Can You Dig It?

Now that the real estate boom in the Bay Area has subsided, more people are focusing on making long-term repairs and improvements to their existing homes. When these projects involve the creation of more living space, the standard approach has been to build an addition. These are either second-story additions, additions behind the existing residence, or a combination of the two.

Another way to create new space which is becoming increasingly popular is to add space underneath your home, which for lack of a better term we will call the Basement Addition. This can involve the use of an existing basement, or the excavation of a portion or all of the crawlspace to create an entirely new area. There are advantages and disadvantages to either type of improvement.

The Traditional Home Addition

Adding a second-story addition allows one to take advantage of natural light and visibility. Architecturally, these spaces can be very appealing. By going up, you are not removing yard space from Piedmont’s typically small lots. On the other hand, the increased visibility may be an issue for your neighbors. In a community where zoning regulations and neighbor input are looked at carefully, these projects can be difficult to get approved.

Second-story additions almost always require additional foundation and structural work to support the upper level, especially in older homes. The need for a stairway usually requires altering floor space at the lower level. And the rear addition requires using yard space which is not always available in smaller properties, due to limitations on the percentage of structure allowed on the lot or setback issues.

We Come From the Land Down Under

And I’m not talking about Australia! When exterior additions are not a feasible alternative, you can consider using the space under your home. The cost of such a project and the quality of the space developed depend on several factors. In general, the greater the slope your house is on and the more dirt you have to remove, the larger new foundation retaining walls become and the higher the cost. Taller foundations may limit the dimension of windows and will require more creative solutions to build a comfortable space while meeting habitability requirements.

Habitable space (aka living space) must fulfill certain building requirments and is significantly more valuable than non-habitable space (aka storage space) since it increases the total square footage of the living space in your home. In order for a basement addition to be considered living space it must be at least 7′-6′ in height, heated, properly insulated, with enough windows to meet glazing requirerments (around 10% of floor area).

Non-habitable space does not have the same monetary value, but it can be an important part of a basement project. Media rooms, mechanical rooms, wine cellars, laundry rooms, and bathrooms are spaces which do not necessarily require windows (or for which small windows are sufficient). They can be created in the portion of the addition which is mostly below grade (underground), reserving walls with larger window spaces for family rooms, bedrooms, home offices, recreation rooms, playrooms, and so on.

Aren’t Basements Cold, Wet, and Nasty?

Absolutely not, if they are built or remodeled properly. With proper heat, insulation, light, ventilation, and appropriate finishes the basement addition should be similiar to the rest of the living space. Concrete retaining walls tend to make basements quiet, cool, and pleasant during warm weather.

The key to basement projects is the integration of structural and mechanical elements with the remodeling of the new space. Most basement additions require the removal and replacement of older foundations and the installation of a modern drainage system as part of the work. Since most of the house is affected by the structures underneath it, there is more going on in a basement addition than in a traditional remodel. The plumbing, heating, and electrical systems for the house may have to be modified or relocated. Since existing basements are not designed as finished spaces, their framing is often irregular and needs to be modified. Properly addressing all of these elements is crucial in planning this type of work.

The Bigger Picture

At a time when habitable space in Piedmont is valued at approximately $600 per square foot, it is easy to see how a large basement addition can add value to your home. Basement additions will generally address existing structural problems as a part of the work. A full discussion at the beginning of such a project of the issues and alternatives outlined above will lead to the best design decisions and allow the homeowner to compare the cost and benefits of the work as part of that process.

Jim Gardner is a Piedmont resident and contractor whose company, Jim Gardner Construction Inc., specializes in basement additions and structural repair. He can be reached at (510) 655-3409.

Solving Residential Drainage Problems

Drainage problems are quite a nuisance for many homeowners in the Bay Area. Flooded basements, garages, and water in crawlspaces and in finished spaces under homes are commonplace. Most people don’t know where to start to solve these problems, or worse yet may have had prior drainage work done that was either inadequate or in some cases actually made their problems worse. A basic understanding of drainage fundamentals may help homeowners make better decisions regarding future drainage work.

Drainage ABC’s

One of the most important things to understand is that there are two types of water that need to be managed- surface water and subterranean water. Surface water is water from roofs, downspouts, patio drains, and water that runs along driveways, walkways, etc. Surface water is primarily rainwater and causes problems during and shortly after it rains. Subterranean water comes from underground creeks and springs, irrigation lines and leaky pipes, or a high water table. Tree roots and fissures in the soil create conduits for water as well. This water is more difficult to manage because it is often not possible to determine its exact source or depth, or in what direction the water is traveling when it encounters your home. It often appears long after a storm and is sometimes present throughout the rainy season or even year-round. Subterranean water is a big problem for many hillside dwellings in our community. This is especially true in older homes where the concrete foundations are porous, shallow or may have some settlement and cracking, allowing for easier water infiltration.

The Correct Solution

To properly solve your drainage problems one must consider both types of water. When we suspect that subterranean water is contributing to a drainage problem, we will often install a subsurface drain (commonly known as a French Drain) in conjunction with our surface drainage. When we install drainage next to a foundation, we will also attach a waterproofing membrane to that wall. This acts as a secondary barrier against water and protects the concrete against further degradation from moisture. The water is then piped to the street under the sidewalk and through the curb either via gravity, or with a sump pump when the house is below the street level. Most building departments prefer that the water is not directed into your yard because it may end up in your neighbor’s yard if it is not properly absorbed into the ground.

Don’t Be Fooled

French Drains are commonly around 3′-5′ deep, but are occasionally much deeper. Substantial amounts of soil have to be removed and replaced with gravel as part of this process. This type of work is not cheap- it is certainly more expensive and involved than surface drainage. Yet it is sometimes the only way (and is often the best way) to keep a crawlspace, garage, or basement space dry while at the same time protecting adjacent foundations from moisture. Improperly designed or shallow drains can sometimes exaggerate the drainage problems and make them worse. It is best to consult with a contractor or engineer who has substantial experience with this type of work before embarking on drainage repairs. A properly designed and constructed drainage system should take care of your water problems and protect your home well into the future.

Written by Jim Gardner of Jim Gardner Construction Inc., a contractor, Piedmont resident, and specialist in residential foundations, drainage, and structural repair

Design-Build Remodeling: An Affordable and Creative Construction Alternative

The consumer in the residential remodeling market can find it difficult to know where to start when they are ready to embark on a home improvement project. The bidding process and the hiring of contractors, architects, or designers can often be intimidating and confusing. What most clients don’t know is that there are alternatives to the standard approach of hiring an architect and getting three estimates. For those individuals who are looking for more of an integrated approach to their project, Design-Build may be the way to go.

The Budget-Driven Approach

Shawn McCadden, a pioneer in the field of Design-Build describes it as follows: “Design-Build is a process whereby the homeowner selects a building and design team to assist with the new construction or remodeling project from conception. The contractor, designer(s) and engineer work together from the onset with the homeowner to manage cost and guide the project design based upon a predetermined budget range.”

In Design-Build cost is a part of the decision making process from the beginning. Alternatives can be presented so that the client can decide on what level of project to proceed with based upon what they can afford (or what they would like to spend). In a competitive-bidding scenario the design has already been determined. However, the actual project cost remains a mystery until the bids come in – sometimes significantly above what the client expected.

Why Design-Build Works

Integrating budget and design create fewer cost surprises. When a client decides to make decisions that impact the project cost, alternatives can be considered to keep the project within budget before the design work is completed and before a construction contract is signed. Since the Design-Build Team is brought together early on, the design and budgeting process can be more efficient since everyone will be working together toward a common goal.

The Process

The first step is the initial meeting between the client and the Design-Builder (usually a General Contractor) to define the scope of the work and the budget. When the client agrees to move forward, they sign a Design-Build agreement. This agreement establishes a cost for the design, which is generally a flat fee based upon the project budget, or it may be an hourly cost. Some projects may be simple, involving only the owner and Design-Builder. On larger remodeling projects, there may be several meetings with various team members prior to construction. The design team works with the owner to make the best decisions and materials selections that fit the budget. Once the design is completed and the price is finalized, the construction agreement is drafted and work will begin.

The goal of Design-Build is to create an integrated process for construction projects. The client is part of the creative work, helping make decisions that affect the project cost. By working together as a team towards a common creative and budget goal, we feel that Design-Build provides opportunities for a more enjoyable and affordable construction experience for everyone involved.

Written by Jim Gardner. Jim is a Piedmont resident and President of Jim Gardner Construction Inc.
You can contact him at (510) 655-3409.