Engineering
I am often asked by my clients if we should use a masonry exterior wall or one that is framed in wood.
Masonry walls consist of concrete blocks stacked up from the slab to the full height of the wall. They are placed in beds of mortar and strengthened with embedded reinforcing steel and hollow cores full of concrete. The strength is dictated by wall thickness, height and density of reinforcement and, of course, loading conditions. Framed walls consist of wood studs usually 16" on center with a stiff sheathing material, water proofing and some sort of siding on the outside such as stucco or siding. Let me answer a few common questions:
Can termites be a problem in wood framed homes?
If the framed wall is built correctly the answer is "no". Pressure treated plates are used at the bottom of the wall. Termites hate PT wood and won't eat through it. Also termite shield should be used. This is like flashing and is placed under the wall and extends out to block passage of subterranean termites in their attempts to travel up the wall. Those and routine maintenance, after construction, such as inspections and treatment allow homes to last a long time. There are many framed homes that are several centuries old which stand as proof that such construction methods are valid.
Is a masonry wall stronger than a framed wall?
In general, a framed wall can be built with adequate strength to handle hurricane winds and other forces. A wooden wall with proper sheathing, nailed properly, is quite strong. A masonry wall is also quite strong. Its strength is a function of its thickness, its height as well as the reinforcement used.
What about Cost? Would masonry or framed walls be cheaper in the long run?
Siding for a framed home can cost more than the typical stucco finishes used over block walls. However other factors, including speed of construction, cost of materials and labor tend to make framing an overall less expensive approach.
What about insulating masonry walls and framed walls?
Insulation is always a challenge with masonry walls. The blocks themselves are not good insulators. Insulation is usually achieved by placing a foil over the pressure treated furring strips, or foam sheets over the wall and can even include filling the cores with insulation. None of these achieve insulation as high as that achieved in a wood wall. Wood framed walls are usually insulated with batts ranging from R-11 right to up in the 20's, depending upon wall thickness. Wood is generally easier to insulate to higher levels. One advantage of masonry is that it has a higher thermal mass which will tend to regulate temperatures a bit better.
Does the relative thickness of masonry walls take up more room in the house?
If one uses a standard 8" masonry block and compares it to a typical 2x4 exterior wall, one can instantly see about a 5" different in the amount of each exterior room that is taken up by the wall. Framing does take up less room.
These are just a few factors to consider. Framing the exterior walls of a home is an excellent way to proceed. Interestingly, most homes that I design are masonry because most folks tend to feel more comfortable with masonry walls. There is a perception of additional strength. But, frankly, the facts indicate that this is a false sense. If done properly (and it is important that it be done correctly) framing is a better value.
Looking to Build your own home yourself? Here are the Pros and Cons - in a Tough Economy
Should you build your own home without a contractor? There can be a strong incentive for the owner to take on the building project and hire the subcontractors and buy the materials directly.
Managing one's own building project can be exciting but it can, at the same time, be risky. There are booby traps which, if not handled, will siphon away any savings. Considering being your own contractor? Here are some pros and cons:
Pros
- Saving Contractor Fees - A contractor tallies up the cost of materials and labor and adds 15% to 25% on top . This covers overhead costs and profit for his troubles. A viable markup is about 20%. You can save this markup by being your own contractor.
- Control - A building project involves dozens of workers. As contractor you are boss. You work directly with these people. You make special requests and assure the work is done to your own standards. Owners can often spend more time on the job than the professional contractor.
- Changes are relatively easy to make - Perhaps you find a good deal on fixtures or materials. Perhaps you find a place for a plant shelf, enlarge a closet or move a door. Good design and specifications will reduce the need for these changes but opportunities to change will be usually be found. As contractor you can accomplish these with minimum hassle.
- Pride - We have all felt the pride of accomplishment. It is a good feeling. Contracting your own home will give you a feeling of accomplishment that is nearly unmatched.
- If you're financing your home, banks will not like it. Regardless of your experience, banks want the job done through a licensed construction company. There are many reasons: Owner-builders can involve the project in activities that the banks can't condone ranging from "under the table" deals with unlicensed sub Contractors (resulting in lack of warranties, shoddy workmanship and many other problems). Additionally, the inexperienced builder is will likely to miss and allow errors to occur that are expensive to fix or are ignored and covered up. This can reduce the value of the home. Unless you are looking to finance your own project, being an owner-builder will be a problem.
- An experienced builder is aware of many things as they oversee a building project. Situations are noticed by the pro that may not become a real problems for several months. These can be handled when discovered. This foresight is a mark of an experienced builder. It is an awareness created by experience. If the Owner-Builder lacks that ability regarding construction there can be expensive ramifications.
- Some sub contractors and material suppliers take advantage of inexperience. They may provide bids for services and products that are not complete - then charge extras later when you discover that a vital aspect was missing. Also subcontractors know that it is often more difficult to deal directly with owners due to inexperience as well as a "this is my baby" attitude than can be burdensome to them. Prices of materials and labor can be higher in the long run - eating into any savings.
- Time is a factor. Contractors earn their fees. A well-run project requires lots of attention - including obtaining bids, managing subcontracts, creating material lists, monitoring the work, getting inspections and babysitting the inspectors. If you are retired or not working this may not be a problem. It is important to remember that the time you spend is valuable itself however only you can judge its true value.
As in most beautiful things, beach homes are easy to appreciate and love, but there is a significant background of technical and legal issues that must be met to bring them into being.
The undertaking, like so many in our country, is now mostly owned by governmental regulators who act, almost daily, to protect just about anything and everything that comes to their minds. Restrictions have become most onerous. But they are finite and can, with professional guidance, be handle.
Here are five 5 issues, unique to building on a beach, that need to be considered:
Elevation - Determined by zoning, the elevation of the main floor of the structure must be considered. This is established as a BFE (Base Flood Elevation) which is a specified height above sea level. It is required that the bottom of the lowest horizontal structural member be at or above this elevation. Finish floors will generally be higher. It is VITAL that this be done correctly and verified by a registered surveyor. I have seen projects built just inches below these requirements which had to be demolished and rebuilt. The officials take this quite seriously.
FEMA - The Federal Emergency Management Agency has developed codes and requirements that affect structures on the beach. These include what types and the sizes of enclosed spaces that may be built on the ground (below the required elevation), the types of materials allowed, electrical restrictions, and many other requirements. Also, if one intends to enclose the space under the home (for parking or storage) the enclosing walls must be designed to break away during a storm event. These are called “break-away” walls and their purpose is to allow storm water to flow naturally without hindrance.
Pilings – Beach homes will usually be on stilts (columns). These will be supported by pilings which are driven into the ground. Pilings are designed to hold if a portion of the soil around them erodes away during the storm. Pilings are designed by a Geotechnical Engineer who specializes in ground investigation and design. Additionally, a Structural Engineer will assure that the loads are adequately supported against water, wind and gravity forces.
Windborn Debris – Doors and Windows must be designed to withstand significant winds as well as the impact of high-velocity projectiles. These are known as “Impact Resistant” windows and doors and can be purchased from numerous manufactures.
DER – The Department of Environmental Regulation will be intimately involved. They assure that wetlands are considered, beach features remain undisturbed, and that wildlife is protected. Lighting is controlled so that beach mice and sea turtles are not adversely affected by the night lights coming from the structure. Additional setback requirements (in addition to the local requirements) are sometimes imposed by DER.
Beach home design, while exciting and aesthetic, is quite technical. However, many consider it worth it to achieve the ultimate in living in Florida and southeastern coastal states. The requirements are numerous – but finite. There are only so many.
Hiring a good professional designer is your best bet to assure that you are guided through the process thoroughly and beautifully.
