Safety Home Improvements
Post-tension slab foundations are found in newer homes. Here in the Bay Area, a structure’s foundation needs to withstand not only the load of the building, but expansive soils, and the ubiquitous earthquake. Certain foundations are better at handling these conditions, and are seen more frequently here. One of these which is gaining popularity in new construction is the post-tension slab foundation.
What is a Post Tension Foundation?
Post-tensioning is a technique that was developed and first put to regular use in the 1970s, and approved methods have been published by the Post-Tensioning Institute (PTI), a nonprofit organization, since 1976. Sometimes called post tensioning, or simply PT, this is a type of slab foundation with added reinforcement.
In essence, a slab foundation, aka a slab on grade foundation, is a concrete base only a few inches deep, sitting directly on earth. You might see this for a small shed or playhouse, but larger structures are almost always reinforced, usually with rebar, and a fabric water barrier is lain out before the concrete is poured.
A post-tension slab is reinforced with grids of steel cables cased in plastic sheathes instead of rebar. After the concrete has hardened around them, the cables are pulled taut with hydraulic stressing jacks. This pre-stressing of the concrete creates added compressive strength to the foundation.
Sometimes things seem to come in waves, and awhile back the waves that found me seemed to all be about unsafe electrical panels in homes which are either risky or potentially risky. I read a home inspection report for a house with a Federal Pacific Electric Company (FPE) panel that encouraged home owners to replace that type because of the risk of fire. Then I met with a potential seller client who was aware of a fire on his block due to a panel failure and was experiencing issues with his Zinsco electrical panel which seemed dangerous. Having two of these red flags thrown down at once did get my attention.
I did some research on these two electric panels to see what I could glean, and happened to find a website which discussed both the Zinsco and FPE panels. This site includes photos of what happens if an electrical panel fails. I found it exceedingly helpful, and think it’s worth sharing widely.
For safety’s sake, please go check the type of electrical panel you have, and sub panel too, if there is one. DO NOT attempt to pull off the dead front (the part which is gray in the image to the right) – only a licensed, qualified electrician should do that.
All of that said, SOME home inspectors will flag that there’s a FPE or Zinsco panel at the property, but will not directly say that it should be removed, but will instead suggest that sellers or buyers contact a licensed electrician about it. Most home inspectors, though, now go farther and do recommend changing these out. Some won’t comment at all, though, so it helps to be an informed consumer.
One more area to investigate is Sylvania or GTE-Sylvania panels. Some of them are designed similarly to Zinsco, and may consequently have the same risks. Not all of them, though, are in this category. A licensed electrician will need to inspect and inform you on this issue.
If you have an older panel, or Federal Pacific Electric Company or Zinsco panel, you may want to investigate replacing it. Please do some research on this topic if you have one of these panels in your home, especially. It may not be universally believed that they should be replaced but this is something to check out, at the very least, if you have one of these in your home. Buying a home? Ask your property inspector about the reputation of the panel. Sometimes home inspectors won’t mention it one way or the other unless they see symptoms of overheating or something similar. Perhaps it’s fine now, but should be on your list of things to replace over time for an added measure of peace of mind.
I recently published a piece on post-tension slabs, which is more used in new construction, however it’s not the most common type across existing homes in the South Bay. While basements are not often found in the South Bay, crawlspaces are. You’re most likely to encounter raised perimeter foundations.
What is a Raised Perimeter Foundation?
A raised, perimeter, or raised perimeter foundation is one that supports a structure while lifting it a few feet above the ground level, as the name implies. It is called a perimeter foundation because the exterior walls are held up by a reinforced concrete stem wall, while the body of the house is supported by a post and pier construct. (In earthquake-free parts of the world, the stem wall may be brick or cinder block.)
This type of foundation is usually only raised around 1-1/2’ – 2’ high, one or two stair steps above ground level. Much taller would make a top-heaviness that becomes less stable against seismic force.
Alternatively, some floors might be set quite low. Two rooms in my single-story house are a step below the rest. They are still raised on posts and piers, but they are distinctly lower than the rest. This is called a sleeper floor. In the crawlspace, this translates to very tight quarters, and I have met professionals who will, and who will not, be able to work in that space.
What is a Post and Pier Foundation?
Post and pier, or beam and post foundation, supports a structure by raising it on individual posts distributed evenly beneath a structure. Each pillar of support consists of three parts: the pier, the post, and the beam.
The pier is a vertical anchor set deep in the ground, usually made of concrete (but occasionally other resistant material like steel). The pier rises a few inches above ground level and is attached to a vertical post. The post, or column, is generally foundation-grade treated wood. This post attaches to a horizontal beam, or girder, which directly supports the floor joists. Occasionally, the pier may act as a post and connects directly to the beam, but that is very uncommon in my experience.
Post and pier foundations can be built without the perimeter wall, but functionally it is very different. You will often see decks built this way, including decks that are attached to homes with a raised perimeter foundation. Without the continuous stem wall the cost to construct is significantly less, but the resulting structure is more vulnerable to the forces of nature, to lateral seismic force, and to pests and wildlife. It also has greater airflow beneath, which is good in places with regular flooding, but provides less insulation from below.
If you are buying or selling a home built before 1960 in California, you’ll likely have to get or complete a form regarding earthquake hazards at the home (some people / situations are exempt) called the Residential Earthquake Hazards Report. The is written and mandated by the State of California. Question # 7 asks about homes with a living space over a garage – this is referencing soft story construction. Many home buyers and sellers would benefit from understanding all of these questions and why the responses matter for earthquake safety. Today we’ll focus on the seventh one.
Residential Earthquake Hazard Report for pre-1960 construction
Soft story construction can also related to office buildings or store fronts on the first floor with large windows or doors rather than solid walls and more floors above it.
The danger arises from the lack of sheer wall in case of a quake. The all glass windows on the first floor, or big carports or garages, are simply not as strong as a wall, and may give way in the case of shaking. For that reason, many are bolstered or reinforced. I wrote about it earlier this week in my Move Move2SiliconValley blog, please read more there: Is your home safe in an earthquake?
What is a cripple wall? (on my popehandy.com site)
If you are buying or selling an older ranch style house or historic home in Silicon Valley, there’s a good chance that original bedroom windows may be smaller or higher than your home inspector might like. What is the big deal with the height or size of the windows? The inspection report may mention ingress and egress. What is that all about?
For fire safety, it’s important that:
- bedroom windows be an escape route for persons in the home (egress) – for this, they must be low enough to the ground and big enough so that children and adults can both get out in case of an emergency
- emergency responders such as fire fighters, with their large backpacks on their backs, can get in through the same openings (ingress)
When windows are too high, kids, and perhaps adults, cannot get out through them. And no matter how low or high, if the windows are too small, emergency personnel cannot enter through them.
How big and how low do the windows need to be?
There are varied requirements, and exceptions, depending on whether the home is new construction or a remodel. Additionally, there are different rules for basements and 2nd story bedroom windows. Cities and towns each have their own codes, too. Your best bet is to check with your particular town or city to see what you must do if remodeling or replacing your windows.
In Los Gatos, ground floor windows must be
- no more than 44″ off the ground
- at least 20″ wide
- at least 24″ tall
- There are additional requirements, though – please see the link at the bottom of this article to view the details.
When remodeling your home and switching from single pane to dual pane windows, many people will be tempted to use the same sized windows with the new replacement set in order to save money, and in many areas, skip the need for permits and finals by not disturbing the stucco. But rather than target the least expensive way to upgrade your windows, I’d like to suggest making safety a priority. Upgrade not just your home’s energy efficiency, but its safety too.
Next is a ranch style house in which the windows have been replaced, but they are fairly high off the ground and the openings are not big enough for a firefighter to get in.
And a ranch style house with newer and enlarged bedroom windows – low to the ground and bigger openings for fire escape or rescue.
I found many related articles on line with the particulars about size. This one seemed especially good, so I’m including the link here alongside info from Los Gatos and San Jose on replacement windows (each town or city may have slightly different requirements):
Buying or selling a Silicon Valley home with stairs? The building code has a lot to say about what is and what isn’t legal or ideal. Older homes may have staircases or rails which don’t match today’s code, but were acceptable when they were constructed (they are legal!). Newer homes are built to a higher standard, and are safer for that reason. Sometimes, the issue isn’t how they were built, but rather that home owners personalize their stairs or guard rails in a way which is unsafe (and that’s not legal).
What are some of the things you want to look for in a staircase?
There are many elements that the code addresses, such as
- when you can have just one hand rail and when you need one on both sides of the stairs
- what the riser height needs to be (whether it is a tall or shallow step)
- the width of the hand rail, where it’s placed, how much clearance it has (so you can wrap your hand around it)
- how the hand rail should terminate
- how long or deep the step should be
- the amount of head room needed
- different requirements for exit routes, indoor and outdoor stairs
- and many more – you can check out the list here on the Inspectapedia website
Guard rails and balusters
Today I want to focus on the staircase railing and guard rail, specifically the distance between the balusters (the balusters are the vertical rails under the hand rail).
The guard rail is what keeps you from falling off the staircase on the open side, if there is one. The hand rail is the part you hold onto as you ascend or descend the stairs.
This first photo shows a newer staircase with a wooden hand rail and wrought iron balusters which include decorative adornments. Notice how close they are, and how impossible it would be for the little dog in the image to somehow fall through the gaps between the balusters. It is a very effective guard rail, even for the smallest member of the family!
The building code today, for new construction and staircase remodels, insists that the gap between the balusters be no more than 4 inches to create a safe guard rail. This particular home’s staircase lines up with that standard perfectly.
Older properties, built in the 60s or 70s, may have stair cases with larger gaps between the balusters, such as this:
The image above represents the spacing sometimes seen in older properties. It is an effective guard rail for adults and larger children, but may not be safe for babies, toddlers, and small children. Parents of toddlers may want to get some sort of safety mesh or other barrier to make sure their kids are safe on stairs with such a big distance (more like 6″ rather than 4″). There are many child safety products available to address this issue.
And not too long ago, I saw a staircase that was modified in a scary way – nearly all of the balusters had been removed!
For several years now in California, having a carbon monoxide detector has been required in virtually all homes in The Golden State. This is not a point of sale requirement. It is a requirement for all residential dwellings which burn gas in any capacity (stove, furnace, etc.), or have a fireplace, or an attached garage as a matter of public safety. They are exempt in all electric homes that do not have an attached garage or fireplace.
Where are the carbon monoxide detectors to be placed? The carbon monoxide detectors should be on every level of the home, including the basement. If you live in a multi story home with the garage at the bottom, you do need one at that level also (just inside the door, once you are in the habitable area) as well as on the main floor, bedroom floor, and any other level you may have. In a single story home, just one carbon monoxide detector is sufficient.
Additionally, carbon monoxide detectors need to be in the bedroom area of the home. If a bedroom has a gas fireplace or wood burning stove (or any other fossel fuel source of heat), there must be a CO detector in the room. Otherwise, in the hall is fine. If bedrooms are not all in one part of the home, there needs to be a detector near each bedroom.
The cost of the device ranges considerably – from less than $10 each to more than $200 each. Some are plug in, some battery only, some feature LCD displays. Some are combination smoke detector & carbon monoxide detectors. Nest makes a CO alert, too. We put a First Alert detector in our house, and the cost was around $20 – $30, but there are many brands from which to choose. (You can also buy portable CO detectors.)
Once installed, it should be checked periodically (along with your smoke detectors) to make sure that it is functioning properly.
Remodeling your home? When you apply for permits, be aware that the city or county inspector who visits your property will be looking for smoke and carbon monoxide detectors. If you don’t have them where needed, your remodel will not pass inspection. Your inspector will need to return, and normally that results in an extra cost to you.
Carbon monoxide poisoning can be very dangerous, to the point of death. If you don’t have a detector, go get one immediately.
From the CalFire site (pdf):
From the City of San Jose: http://www.sanjoseca.gov/index.aspx?NID=5344