Do I Need a New Foundation?

Most clients have no knowledge about their foundation and its condition until they begin to notice problems inside their homes- generally settlement cracks, sticking doors and sloping floors are indicators that something is amiss.

Though there is no cut and dry formula to show when a foundation needs to be replaced, there are a number of indicators which when looked at together should point the direction one way or another.

1. Are there drainage issues?

Drainage is the #1 culprit, and leads to settlement, cracking, and deterioration of concrete. Older concrete is somewhat porous, and water will soak into the material causing it to deteriorate. Since most older homes have nonexistent or improperly installed drainage systems, it is important to have the drainage issues addressed- either as part of the foundation work, or if the foundation is in decent condition to avoid an expensive foundation replacement project in the short term.

2. Is the concrete deteriorating?

By poking around with a screwdriver, we can see how intact the concrete is. Often concrete with lots of sand in the mix that has been subjected to drainage issues will be so soft it can be pulled apart with your fingers. This condition can be of major concern, as this concrete has very little strength and could liquefy in an earthquake. The harder the material the better. Appearances can be deceiving. Some of the ugliest concrete with lots of rocks and voids can be quite strong and is less of a concern.

3. Are there cracks?

A few cracks in older foundations is expected, but lots of cracks, especially one’s that are ¼” or larger can be problematic. Since older foundations typically do not have rebar in them, once large cracks occur the concrete can separate into sections that can rotate or settle independently from one another, causing settlement or shifting in the house above.

4. Is there rebar?

Most homes built before 1930 or so do not have steel reinforcement in them. Rebar helps to strengthen the concrete and hold it together in the event of cracking from settlement or earthquakes- cracks can still develop, but they remain hairline and don’t pull apart. The modern foundations we build have at least 5 pieces of rebar running horizontally, and verticals every 12” so they are heavily reinforced.

5. Depth and location of the concrete.

Often older foundations are not of sufficient dimensions to work effectively. If the footings are not at least a foot or more below the grade level they will be subject more to movement in expansive soils and drainage issues. If they are not 6” or more above grade there can be water issues at the framing level causing dry rot issues above. And if the soil is excavated on the interior of the basement or crawlspace too close to the foundations or if the footings are functioning as retaining walls and they are not designed properly they may settle or move, and they may create drainage issues leading to more settlement.

6. How old is the concrete?

Concrete from the early 1900’s that is still in place in older foundations is often in poor condition. Since most of the homes we work on in the East Bay were built between 1900 and 1930 this would definitely apply to them. Again, drainage, lack of rebar, improper dimensions, cracks etc. are much more pronounced in older foundations.

When all of these elements are looked at together, it is easier to get a sense of how your foundation is performing in these key areas. In many situations, where I give the foundation an overall score of 1-3 on a scale of 1-10 the need to replace is fairly obvious. In the 4-5 area it often becomes a more difficult question, where the client needs to consider their resources, how long they plan on remaining in the home, etc. If the foundation is in fair condition but in need of drainage work which might add another 20-30 years to its lifespan, that is often a reasonable alternative course of work. When the condition is poor, however, it generally does not make sense to do a drainage only project, since that work would need to be torn out and redone sooner rather than later as part of an inevitable foundation replacement.

Water is the REAL ENEMY for most homeowners!

The bottom line is that water is the main culprit implicated in most of the damage created to the exterior of your home, and can lead to interior damage as well. Maintenance problems such as chipping paint and damaged trim, poor flashing details around windows, decks, porches and doors, a roof which is leaking or needs replacement, or the lack of a proper drainage system around the home will all lead to potential problems when water comes into contact with your residence. Rainfall and underground water sources such as creeks and springs, a high water table, irrigation systems, leaking water lines or broken or disconnected drain lines- all of these water sources can wreck havoc on your home. Lets discuss how the different components of your homes exterior are affected.

The Foundation
Many of the older homes in our area have foundations that are in poor condition.

But this is not merely a function of the age of the concrete. Since most of the foundations were installed without drainage systems moisture in the ground adjacent to them, whether from rainwater or subterranean water sources, is causing them to deteriorate. Concrete becomes porous over time, and the water will saturate the interior of the concrete and cause it to break down. Water in the soil adjacent to and under the foundation, in conjunction with the expansive clay soils present on most of our properties, will cause the foundation to move as the soil shrinks and expands between wet and dry periods. Since older concrete is generally unreinforced it can settle unevenly causing it to crack, allowing more water to enter causing settlement. This often appears as cracks in walls, ceilings, and around doors and windows, along with sloping floors. Installing proper drainage will help alleviate these types of problems.

Exterior Walls
In older homes the stucco was often brought all the way to the ground. Since there are boards behind the stucco that were in contact with the soil, this gives termites access from the ground. When the paint and caulking are not maintained water can get in around doors and windows, leading to dryrot. Poor flashing details around porches, decks and roofs and leaking gutters and downspouts can allow water into the building as well, and termites love warm moist spaces. Foundations should always be at least 6”-8” above the soil level to prevent termites from entering at the base of the exterior walls. Foundations that are in poor condition should be replaced with taller, steel-reinforced footings. For foundations in better shape, concrete termite curbs can be installed at the outside of the building to create this clearance, and they are a more reasonable alternative to replacement. Painting and caulking should be properly maintained and trim should be repaired or replaced if damaged. Gutters and downspouts should be repaired if they are leaking, and they should be properly sloped to drain properly, flashed and kept clean to make sure they don’t leak into the exterior walls.

Interior Damage
When your foundations move for the reasons described above, this can lead to cracking and settlement on the interior walls and ceilings, doors and windows that stick or won’t close, etc. Sloping floors reflect foundation settlement or damage. By correcting the moisture problems first the interior damage should be minimized, at which point it will be appropriate to undertake repairs.

In summary, water is often the main factor leading to a large variety of structural repairs. Soil problems, earthquakes, and poor construction- these can also cause damage, but they are less common. Water is a subtle culprit that affects many older homes over an extended time frame, increasing with the age of the homes foundation. The sooner the maintenance issues can be corrected, the less they will affect the structure as a whole and the lower the ultimate cost of repairs will be.

Hidden Structural Damage – When your front stairs may no longer be supportive

We were recently doing some minor repairs to a set of front concrete stairs when they suddenly and inexplicably collapsed into a pile of rubble in front of the home. After overcoming my initial dismay, I began to consider what might have caused this dramatic event. If this were to have happened when the homeowner was entering the house they could have been seriously injured. From above and below the stairs appeared to be in reasonable condition.

stairs after collapsing
Stairs After Collapsing
On closer inspection it was clear the concrete steps had been patched in the past, allowing water to get into the support framing. The only waterproofing under the old concrete protecting the framing was building paper (tar paper), which has a limited lifespan when it is in frequent contact with moisture. Since the old concrete had no steel reinforcing (rebar), once it settled due to the poor support framing it actually broke up into several smaller pieces. The wood form material underneath the stairs concealed this cracking. Because of a lack of proper flashing where the steps met the stucco sidewalls, water got into the walls and rotted the studs. This framing made up the structure supporting the steps, but it was also concealed by the stucco. All it took was the removal of one 2×4 and the whole thing came crashing down. If you figure at least a couple of cubic yards of material you are looking at approximately 10,000 pounds of concrete!!!!

New Stair Installation by Jim Gardner
New Stairs
Front stair and landing replacements are becoming a significant part of our work, and with good reason. This dramatic collapse shows what can happen when the damage is severe, and why it might go unnoticed. With older concrete structures that show signs distress one should make test openings in the stucco and the support framing to look closely at their condition. If they are in poor shape it might make sense to consider replacing the whole structure. Sometimes new foundation work is required, but not necessarily. We would demo the existing concrete steps and support framing and replace the wood with new pressure-treated material, usually of a bigger dimension and with narrower spacing. This usually requires some detailing from our structural engineer to design the supports to modern engineering standards. On top of the framing we use pressure-treated plywood and then a bituthene roofing membrane for waterproofing, along with metal flashing at the sides adjacent to the wall framing. The final step is the steel-reinforcing for the new concrete. The end product is a much more supportive structure which will provide a safe entrance to your home for many more years to come.

All Drainage Systems Are Not Created Equal

Why A Watered Down Solution Can Do You More Harm Than Good

Having spent a lot of time in recent years reconstructing a number of ill-conceived drainage projects, it has become fairly obvious that there is a serious lack of knowledge on the part of both the installers and homeowners as to the ABC’s of a good drainage system. Unfortunately, putting in a poorly designed (and often inexpensive) system can create problems that weren’t there to begin with, leading to extensive repairs down the road.

One of my best examples came several years ago on a project we did in Oakland. The homeowner came to me complaining of settlement problems in their new kitchen. Tiles were cracking, and the floor and cabinets were out of level. This was on the main floor. At the basement level there was a large crack running the length of the house in the slab floor, about 4′ in from the outside wall. Obviously there were some settlement problems, but what had caused them?

After discussing the problem with my client, I learned that several years prior they had installed a drainage system (at the cost of around $3,500) that was level and around 2′ deep, with a slight slope towards the front of the house. It was obvious to me that this water had nowhere to go, and it was sinking into the ground adjacent to the house causing it to settle. What should have been installed was a system starting at the front corner of the house, below the level of the adjacent basement floor, starting at about 4′ deep and terminating in the rear yard in a drain-field at a depth of about 6′. This system would have cost them around $10,000.

Did they end up saving any money? Not after the $50,000 they had to spend to replace the damaged (brick) foundation, structural and framing repairs, new drainage system, stucco repairs, kitchen repairs, slab repairs, etc. (see the picture below). The contractor was long gone, and they were out of pocket a lot of money.

 

So what are some of the key points we need to know to avoid these types of problems in the future?

  1.  Don’t mix up your sources of water. In the Bay Area we need to consider both surface water and subterranean water as possible problems. The surface water (from your downspouts or patio drains) is transmitted through solid drainpipes to either a drain field or to the street (depending on your City regulations and site conditions), and the underground water is collected in perforated pipes by a deeper system commonly known as a French Drain. These pipes need to be kept separate in the system and not co-mingled. Inexperienced drainage installers sometimes dump the surface water into the French drain, which places excessive water into the trench that sometimes creates a bigger problem under your home.
  2.  Water runs downhill. It may sound rather simple, but the drainage system needs to be sloped correctly to its termination point. A general rule of thumb is 1/ 4″ per foot minimum for the downspout drainage, and 1/8″ per foot for the French drain. This often means that on a big system the end of the drainage is a foot or more below the starting point, and the trench needs to be sloped accordingly. On level lots this often requires sump pumps to be installed due to a lack of slope.
  3.  Place your drainage adjacent to your foundation where possible. When you can use an excavator to do the work, it may make sense to place the drainage away from the building if there is a substantial cost savings (versus a labor- intensive hand-dug system). Since most of our systems are hand-dug due to limited access, we like to put them up against the foundation for a couple of reasons. First, if the drainage is away from the building there is an increased possibility that some surface water will still get between the new drainage system and the building and go under the house. Second, by trenching next to the house we can attach a waterproofing membrane to the foundation that will protect the foundation from continued exposure to moisture. This may extend the life span of an older foundation. As long as you are careful not to undermine the foundation during excavation, digging next to the foundation should not be a problem.
  4.  Your French Drain should be deeper than the level of your problem. Subterranean water from creeks, springs, and other sources can run very deep, and sometimes runs year-round. If the drainage system that is built on the uphill side of a basement or crawlspace is not constructed to a depth below the level where water is getting in you cannot be sure that your problem is solved. In fact, it can sometimes make things worse if the trench now collects larger volumes of water that may enter the building. This principal is often violated because deep drains are substantially more expensive than shallow ones. Sometimes the drainage can be 6′ to 8′ down, or even deeper in certain instances.
  5.  Watch where you dig. Water always wants to seek a lower level, and it will find its way into your sub-area through any opening or penetration you create for it. I see a lot of situations where site drainage created as part of a landscaping project will create shallow trenches in the yard that bring water adjacent to the foundation, creating drainage problems in the basement or crawlspace that are new.

Make sure your drainage design plan is sound before embarking on any new drainage project. By paying attention to certain basic drainage principles and by doing the job right you will avoid a lot of problems in the future.

Earthquake Retrofitting Products and Services

Earthquake (or seismic) retrofitting involves stabilizing your house to help minimize any potential damage in the event of an earthquake.

It is not an all or nothing proposition. There are certain retrofitting basics that relate to most homes. These usually involve doing work in the accessible areas of the basement or crawlspace. More advanced projects often included strengthening the upper levels of your home, areas around openings such as garages or porches, or addressing other structural weaknesses. Basic retrofitting can often be done using standard details that Jim Gardner Construction- Structural Contractor can show you. These projects are often referred to as “voluntary sub structural strengthening “. We also work closely with a local structural engineer to provide low cost structural details so you can avoid costly engineering fees and over-designed projects in more complex retrofits.

  • Foundation Bolting
  • Earthquake Retrofitting
  • Seismic Retrofitting Earthquake Repairs
  • Seismic Repairs
  • Sheer walls
  • Hurricane Ties
  • L70
  • Foundation Anchor Plates
  • Holdowns
  • HD5 or PHD5A
  • Strong Walls
  • Anchor bolts
  • T- Straps
  • A35
  • Epoxy
  • Post base brackets
  • Sub-structural Strengthening

Jim Gardner Construction- Structural Contractor can provide you with an expert consultation, and help you make an informed decision about your retrofitting options and their relative costs. Jim Gardner will make sure your home has the best protection available against the potential devastation of the next earthquake, and that you and your family will be safe.

The Homeowner’s Guide to Earthquake Safety contains many internet based resources. Jim Gardner Construction is providing this information to homeowners interested in improving the earthquake safety of their homes. The content provided is intended to provide a quick reference to these web sites and files.
http://www.seismic.ca.gov/hog.htm

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.