Piers You’ve Probably Overlooked!

I know that most professional installers are very conscientious when it comes to proper pier placement. But with all the variations in the installation instructions, some piers are often missed. Even while the manufacturers are required to identify “point load support areas” many areas are still overlooked.

One example of identifying point load locations.

Let’s take a quick look at some of manufacturers installation instructions to see where they do or do not require “point load” support piers.  


I started with the new Clayton Installation Manual to see exactly where they require point load support. They want supports at each side of exterior doors in the side wall. No support is needed if the door is on the end wall supported by a “steel header”. So, do we need supports if the door is at the tail end of the home if it doesn’t have a header? They go further and say no support in needed for doors in the side wall if the chassis I-beam spacing is 112”.

A support pier may be needed at through-the-rim crossover locations.

Support is also required at locations where through-the-rim joist heat duct penetrate the floor rim-joist.  I have seen this requirement in a few installation manuals, but not much further direction. I don’t know exactly where to position this pier, and I have never seen these areas identified as point load support areas on the underside of any home. 

A support is needed at each side of a factory installed fireplace when located along the side wall or marriage wall, (again with the exception of fireplaces supported by the front chassis crossmember). 

Adjustable outrigger at patio door location. Note the white paint marking the location.

The Clayton Installation Manual does allow adjustable outriggers to replace piers at the fireplace locations and door locations (less than 48”) along the marriage wall or side wall. The Clayton Manual doesn’t mention the use of an adjustable outrigger at the “through-the-rim” heat duct location. (check out page 21 on the Clayton Installation Manual).

So, just for fun, I decided to compare a few other installation manuals, starting with Champion.  

Window configuration creates side wall opening greater than 4′.

When it comes to doors, Champion is pretty clear (page 16). They require a support at each point load including: both sides of doors in the side wall. If the door is less than 48”, adjustable outriggers may be used in place of door piers. “Blocking” is not required for doors in non-load bearing end-walls.  

Here is an interesting one: Champion requires support “Under heavy (400 lbs or greater) items, such as heavy furniture, waterbeds, fireplaces and large fish tanks”. I better have a few extra blocks ready for the next visit from my mother-in-law!

Typical porch support.

What about Commodore/Colony you say? Ok, turn to page 15 in their installation manual. They want support at both sides of exterior doors at the side wall, but not at doors in the end walls. Porch posts always require support. They also want a support at through-the-rim heat crossover ducts, and under heavy items like waterbeds, fireplaces, and mothers-in-laws.  

Here is the curve ball: “…where marriage line openings are greater than 10 feet, intermediate supports must be placed at maximum 10 feet on center”. Some other manufacturers have this same requirement. Others only want these intermediate supports if the home has perimeter supports (evenly spaced under the side walls).

T Brace (pier saver).

I think it’s only fair to say, that Commodore/Colony was the first manufacturer I was aware of to introduce “Pier Savers” for support of patio and other exterior doors! I am a big fan of pier savers.  Look up their “Alternate T Brace” addendum A-7.

Adjustable Outrigger

Skyline requires a support at exterior doors on side walls (not end walls), typical 4’ marriage line and side wall openings, through-the-rim crossover ducts, porch posts, heavy furniture, fireplaces, etc. BUT..Skyline utilizes the adjustable outriggers more liberally than most. Basically you can use an adjustable outrigger to replace a support with a load up to 1,700 lbs. Go to their charts on page 20 of their installation manual for span loads. Some Skyline plants provide the adjustable outriggers with the homes. Make sure you get a copy of the “Addendum to Installation Instructions for Installation of Adjustable Outriggers”   

Shear wall strap needs pier support.

Finally, I checked out Fleetwood, pretty similar to the others, except they want support at “labeled G-2 strap locations” (see page 20 in their installation manual)

At this point you might be thinking, “just follow the pier print”. Well, I checked out a handful of “pier prints”, and most of the locations mentioned above are NOT identified on the pier prints. None showed the piers at the through-the-rim crossovers, or at any fireplaces. Also, the “intermediate” supports at the marriage line is missed by most. One pier print I noticed shows piers that defied any reasoning!

OK, here are the take-aways:

There is no “One Size Fits All”. Make sure you take 30 seconds, and open the installation manual and look under the heading “Install Footings” where you “Determine Locations”. Make sure you know each particular manufacturer’s variations.

Don’t trust the pier prints! Never, Ever! Follow only DAPIA stamped (approved) designs and instructions.

Investigate pier savers and adjustable outriggers! Some manufacturers already approve their use. If yours doesn’t, start asking for approval! The squeaky wheel always gets the grease.

And lastly, don’t invite my mother-in-law to your house!

Talking About Manufactured Homes, Post Harvey & Irma

Over the past few weeks, our industry has received a considerable amount of attention from the media and emergency management agencies. Unfortunately, most of the attention hasn’t been favorable.  Now is the time to refocus the attention on manufactured housing that is completed by professional installers, and meets or exceeds the various elements of the Manufactured Home Construction & Safety Standards (HUD Code), to provide not only affordable housing, but housing that is durable, high quality and above all, safe. Let’s discuss a few facts that you can share with your customers and the general public: 

  • There has not been a “mobile home” produced in over 41 years. You are installing and/or selling “manufactured homes” and the difference is significant. Don’t diminish the immense improvements that have been made by the industry since 1976. Use the proper terminology!
  • The HUD Code takes wind storm protections very seriously. The country has 3 different wind zones to address areas susceptible to wind hazard. Wind Zone II requires homes to be designed to accept 100 MPH winds. Wind Zone III’s design load is 110 MPH.
  • The anchoring process for manufactured homes has been completely revolutionized since 1976. There are newer anchoring systems available that not only meet the code requirements, but they are considerably easier to install and less susceptible to problems from site grading, frost heave or other environmental problems.  If you haven’t re-examined your anchoring procedures, you need to immediately. Look at a previous posts on this topic.  Introduction to Alternative Anchoring Systems
  • Every new manufactured home sold today is installed by a trained professional. And every installation is required to be verified for proper installation by a building code official or similar code enforcer.

Much of the destruction caused by Hurricanes Harvey and Irma was beyond the ability of any residential building code. Many homes sustained damage from impact of flying debris and flooding, as opposed to wind storm. Did you know you can equip manufactured homes with hurricane shutters to protect large windows and glass doors? Check the home installation instructions under “Complete Exterior Work” or visit www.apawood.org for more information (search for hurricane shutter designs) .

In far too many cases, manufactured homes were damaged due to the failure of carports, patio covers, awnings, and similar after-market additions that catch the wind and impose pressures on the home well beyond the intended design load. I am sure you all know that these types of accessory structures must be independently supported. If you haven’t already, watch this video, Click Here, it clearly illustrates the problems that attached structures can cause.

Remember, the HUD Code is a minimum code. Have you considered offering your customer the next step up? Offering a middle snow load in the south zone? Offering Wind Zone II in Wind Zone 1?  A higher level of performance is a feature that can be easily marketed, and may be instrumental in changing the narrative. Not every buying decision is based in the lowest price. Give your customers options and they just might choose a higher level of performance.

I think the time is right to start talking about the improvements that have been made over the past several years. If we continue with a mobile home mentality, the media and public will remain skeptical of our industry and never learn about these important changes and high level of performance and safety a properly installer manufactured home can deliver!

Water Heater Temperature & Pressure Relief Valve Discharge Pipe

A few installers have raised a question about the discharge pipe for the water heater Temperature and Pressure (T&P) relief valve. Ultimately, should the water heater T&P discharge pipe be run to the exterior of the crawl space? 

I did a little research and quickly discovered that this issue needs much more discussion than is provided in the manufacturer’s installation instructions, or that we can accomplish here! But we should start thinking about it.

The first thing to understand is the job of the T&P valve. If the temperature in the water heater reaches 210° or the pressure reaches 150 psi, the relief valve will open reducing the pressure or releasing heated water to be replaced with cold water. This is  to prevent a potentially catastrophic failure. Just image the power that can be generated when the water starts to boil inside the tank! There have been reports of water heaters exploding and propelling themselves through the walls causing significant damage to the home.

The amount of heated water that can be expelled through the T&P discharge pipe can range from a trickle to a gusher! Either way it enough to cause severe burns!

The manufacturer’s installation instructions don’t offer much guidance. I reviewed several “Complete Installation Checklists and they all state “Dryer vent, range/cook top exhaust, water heater temperature and pressure relief overflow pipe and AC condensate drain installed to the perimeter of the crawl space”.

If you look a little deeper in the manufacturer’s installation instructions, several state “If the home is to be installed on a basement or enclosed crawlspace, install the drain pipe connecting the discharge from the water heater temperature and pressure relief valve to the outside or to a sump”. I did find a few exceptions that clearly state that the T&P may discharge under the home. But bottom line, there is no consistency in the various manuals, and no direction as how to safely extend this discharge pipe to outside of the crawl space.

In my opinion, the installation of vinyl skirting around the perimeter of the home meets the criteria of a crawl space, and I have yet to see any definitions that say differently. So, I guess they are saying to run the T&P discharge pipe outside the skirting.

T&P & water heater pan pipes discharging under the home.

Finally, I double checked the Manufactured Home Construction and Safety Standards (245 CFR 3280.609(c)(iii). It says the “relief valve outlet which shall be directed downward and discharge beneath the manufactured home”. 

So, what should a professional installer do?

If you should decide to extend the T&P discharge pipe to the exterior of the crawl space, keep these things in mind:

The T&P pipe should have an elbow directing any discharge downward.

Any water being discharged from these T&P valves is extremely hot with the potential to cause damage to people, pets or property in the area. Make sure the pipe points downward to about 6” above grade to reduce the possibility of injury! Make sure it is visible, but away from an area where people or pets might be injured.

Any extension of this pipe must be the same size as the discharge pipe attached to the valve. Keep the piping as short as possible (less than 30’ total length), with as few elbows as needed (four elbows are the maximum permitted).  Any horizontal sections must slope away from the valve. Do NOT install a trap, shut off valve, or a cap on the discharge pipe!

Never connect the T&P discharge pipe to the DWV (drainage) system of the home. Should the valve become defective, the occupant would never know, and in the event of a violent discharge, the DWV system could be damaged and people possibly injured. Not to mention possible contamination of the water supply!

I suggest a discussion with the local code enforcer to get his take on this issue. Also, review the water heater instructions and see what they say. Contact the home manufacturer’s engineering department for their input as well.

Unfortunately, there may not be a simple, straight answer to this question. But maybe this discussion will help us to make the best decision to assure the safe operation of these water heater T&P valves.

I would appreciate hearing your comments on this issue!


FEMA requesting Manufactured Homes for Harvey

FEMA has announced that it is asking the manufactured housing industry to produce at least 4,500 manufactured homes to start providing housing for the people displaced by Hurricane Harvey.

Exeter, PA, November 19, 2011–FEMA contractors build a ramp into a temporary housing unit at the Mt. Lookout Community site in Exeter, Pennsylvania. The temporary housing units were brought in to house more than 300 disaster survivors who lost their homes following Tropical Storm Lee. Andrea Booher/FEMA

As a result, you will likely see manufacturers shifting production across their networks of plants. While the plants you may work with may not start producing FEMA homes, they may be called upon to increase production to meet the demand in other areas.

During Tropical Storm Lee and Hurricane Irene that hit the mid-Atlantic region in August and September 2011, FEMA not only supplied temporary housing units to those affected, but also established manufactured housing communities, including all infrastructure needed to support the new communities.

Tunkhannock, PA, November 19, 2011–FEMA contractors clear ground for the temporary housing units that will be brought in to the Highfieds Community site in Tunkhannock, Pennsylvania. The temporary housing units will house disaster survivors who lost their homes following Tropical Storm Lee. Andrea Booher/FEMA

Check out this news report from CBS News for a closer look. CLICK HERE