Reading house plans is not as hard as it sounds, it takes a little practise, someone to point out what the symbols on the page mean and it also helps to be able to picture things in your mind.
When you have a set of house plans drawn up by an architect or draftsmen usually the first page of drawings is an overview of the site that you will be working on, this shows the position of the house relative to the lot lines, road ways and right of ways. It also shows the positioning of the other buildings already on the property or any building that is to be built. A lot of the time this overview page will also have numbers on it that will be around the home and in key areas. These numbers are the grade elevation numbers, they show what the height of the finished grade will have to be around the newly build building. From these numbers you will be able to set the height of the first floor of the house which will set the height of the entire building.
The next pages of a proper set of house plans will show the foundation and footings as an overview (from above looking down).
There should be this same overview for every floor and the roof with details on interior and exterior walls.
What comes next are the elevations, this is the pictures of all the four sides of the home as seen from the outside of the building.
The last pages will be details, cross sections and lists of window, doors and anything else that the architect and engineers deem necessary for the construction of the home.
There are several things you need to understand about house plans;
• Every house plan has a scale. This scale will allow you to measure with a tape measure or a ruler to ascertain the lengths of things on the plan that do not already have measurements. The scale for most plans is ¼” =1’. This means that for every ¼” you measure on the paper in the real world it would have been 1 foot. This is the most common of scales, but a lot of plans depending on the size and scope of the building will use different measurements. Depending on the architect and what they are attempting to draw the scale could change from page to page and detail to detail. It is critical that you take the time to ascertain the scale of the drawing that you are looking at.
• There is always a legend. Depending on what part of the plan that you are looking at there will be symbols that you won’t understand. You will have to look for a legend that will help you identify what they mean. The part of the plan with the most symbols is usually the electrical layout. There are so many different things that go into a home to do with electrical the only way to do a proper layout is to use symbols. The legend will tell you in detail which symbol means which.
• When trying to understand a cross section you must figure out the location of the cross section. This is done by looking at the floor plans that are shown from an overview (birds view); at certain locations around the perimeter of the building envelope you will see symbols that will say A2 or A5 with a line running away from them towards the building. These numbers are telling you that there is a cross section available to look at, the A means it’s a cross section for that floor of the house and the number tells you what cross section it is. All you have to do is look through the plans until you find the corresponding number labeled on a cross section. This cross section will give you a view of that area of the house as if someone cut the building in half as a straight on view. These are extremely important for interior details and to determine how certain loads and beams are to be built and carried from floor to floor.
• There is always a date on the plans, it will state the date and also if the plan is a revision. Revisions are changes to the plans from the original set of drawings that will affect the building or design of the structure. Everyone most make sure that they are working off the same plan with the same date.
The best thing to do when trying to read plans is ask a lot of questions to your builder while you are reading them together. They will be able to explain to you what they mean and then when you are having discussions about the build either over the phone or via email you will both understand what part of the plan to look at.
Village Builders Inc.