How to measure a building?
A measured survey is a survey carried out on a building or site in order to produce accurate drawings, such as plans, elevations and sections. These drawings can then be used as a starting point for any design work.
A measured survey can be carried out by an architect or designer, or in more complex buildings or projects, a survey company may be employed to carry out the measured survey. There is a range of technical equipment available for complex surveys, including 3D lasers, GPS equipment and more. However, for smaller scale projects, it is perfectly possible for a survey to be completed with a tape measure (or disto/laser measure), pen and paper. There are also a number of apps available for the phone or ipad that can assist in the survey process.
In this post, I would like to share some of my experiences with carrying out measured surveys on various buildings from small domestic houses, to farms and even large disused industrial buildings.
You can download this complete guide to measured surveys, along with our measured survey checklist by scrolling to the end of the article!
Arrival on site
The first thing I do when I arrive on site to do a measured survey is have a look around the entire building, so you can get a feel for the layout, where the rooms are, stairwells, etc. This is helpful for when you start to draw out the building.
Depending on the size of the building you are surveying, you may want to break it up into sections, so each page you have a part of the building, so that you can draw it out at a large enough scale to add your measurements/dimensions. You can either draw each part as you go – draw, measure, next area, draw, measure, next area etc. Or you can draw out the whole building then go round and take your measurements. Whatever works for you.
If you only have a tape measure, it is usually best if there are two of you, but you can do it alone, it will just take a bit longer. With a laser however, it is pretty easy to get everything measured alone.
Make sure you start by labelling your notebook or sheet of paper with the project name and either room name, section of building, floor number etc. It might seem obvious now but when you have pages of survey drawings sometimes it is difficult to figure out what is what. You may also find you are not going to be the person drawing up the survey, so making sure everything is well labelled and clearly noted will be really helpful.
I don’t tend to draw a huge amount of detail as generally it doesn’t really add anything. Here are a few of my drawings. Not the neatest or prettiest in the world, but I can generally make sense of them!
A tip on drawing, I use a three colour pen to draw out my measured surveys. I use one colour for general drawing and measurements, then another colour for window information (cill height, window head height), and finally another colour for all heights and levels – ceiling heights, floor levels, steps etc. This is really useful when you are back at your desk trying to figure out what the random numbers are floating around on your drawing.
Start your measuring in one corner of the room and work your way around in a clockwise/anticlockwise direction. This way you won’t miss anything. It is also wise to take a few diagonal measurements to help with accuracy.
Take your measurements at a height where you will pick up the features like windows and doors, usually at about 1m high. It is helpful to take running measurements, along with a full measurement of each wall. Running dimensions mean that there is less chance of making mistakes. It may be more time consuming on site, but I always try and take as many measurements as possible. I would rather spend an extra hour on site doing this, than having to go back again the next day when I realise I have missed vital dimensions.
Make a note of wall thicknesses, which will vary internally and externally. Take to site some stiff card and some tape, so that you can tape up a target for the laser if required. This is really handy.
Here are some ways of representing the measured survey information that I use, feel free to use and adapt to suit you.
Measuring a room
When measuring a room, I would tend to get a couple of overall measurements of the longest walls, along with some diagonal dimensions in case the room is not square, then more detailed measurements of wall to window, window width etc. working your way around the room.
Where possible try to get an overall measurement between two rooms. Using your laser measure from one wall in one room, through the door to the wall in the adjoining room. This helps with linking the building’s rooms together.
Don’t forget to measure ceiling heights, and if possible pick up the floor thickness (usually possible to do in a stair area), which will help with elevations and sections. I usually use a different colour to show all heights, which helps when drawing up your survey back at the office. Make sure you take note of any ceiling height change, any beams or structural elements, picking up the underside height of the beams as you go. Try to note where the ceiling height changes wherever possible.
Measuring doors and windows
Measuring doors, I usually measure the door size, and the general outline frame details. Be mindful that the doors are likely to be the same throughout the building so you may not need to measure every door, but there can be variations. Remember to measure the height of the door and note up on the drawing. For windows, I measure the structural opening rather than the frame. If there is something in front of a window that stops you measuring the cill height, some furniture or a kitchen worktop for example, you can measure the ceiling height and the cill to ceiling height to work out the cill height.
How to measure stairs
Stairs need to be considered in both plan and section or height terms. In plan, we can easily measure the width of the stairs, and the tread or going of the steps. We can count the risers and make note of any landings in the stair. Depending on the complexity of the stair, sometimes it is worth sketching it out separately on a larger scale for clarity.
Make sure you take as many measurements as possible to demonstrate the link between the two floors. When measuring the risers, ensure you take into account the nosings of the steps. Count the steps and mark on the drawing, especially when there are landings on the stair.
For the stair height, if possible measure the height from the top of the stair to the bottom, the overall height. You can then divide the height by the number of risers which will give you the individual riser height. Additional dimensions such as ceiling heights from landings, any cill heights of windows on landings and any distinguishing features should all be noted where possible.
Finding roof heights and details can be difficult and is very dependent on the building. Here are a few tips on how to measure the roof height. If possible it is best to have a disto/laser measure when taking dimensions for roofs.
Externally, try to take a floor to the underside of eaves measurement. Check whether the ground level varies around the building and find some constant that you can measure from. We sometimes use the dpc as a good constant to measure external heights from. In addition to this, if the building has a gable, try to take a floor to the underside of ridge measurement too. This can be hard in daylight with the laser, but persevere!
Next, if the building is brick built or has a uniform facade (regular stonework, blockwork etc), take good flat photographs, and use these to count bricks/blocks and then work out distances from there. Be sure to take a couple of measurements of the bricks/blocks and mortar individually so you can work out the overall.
Internally, make sure you are thorough with your floor to floor, floor to ceiling measurements.
If you can gain loft access this is ideal – make sure you have safe access and it is safe for you to enter the loft space. You can then get underside of ridge measurement from the top of the ceiling joists, and take measurements of the rafters etc. Treat this area in a similar way to any other room, get as many dimensions as you can safely, and take heights and dimensions of purlins and any other features worth noting. With this information you will be able to work out the approximate height of the roof, and consequently the angle. Some laser measures can provide angle measurements using in built inclinometer.
Make sure you get some levels too, take a measurement from the finished floor level inside the loft down to the floor level below.
Hipped roofs are more tricky, but often come together when you have floor areas, eaves heights and internal measurements from the loft access.
Make sure you take photographs of the roof space too, useful when trying to recall rafter and purlin positions and other little details that may have been missed in the poorly lit roof space!
How to measure for drawing a section
You can draw up most of a section from the measured survey you have carried out to create floor plans. There are, however, a couple of things to look out for when surveying for a section. If you know the part of the building you will be taking a section of, it is an idea to check all ceiling heights on that section line. Make sure you also have the room widths, window heights and any other measurements of elements that will be revealed in the section.
How to measure for elevations
Sketch out the elevations and measure key features to help you. If you are using a laser measure, try and measure the eaves and if possible ridge height. If the ground level varies, take a constant feature on the elevations, for example a window cill, and measure to the ground from this point around the building. This will show the changes in ground level. Most of your elevations will be possible to draw from the floor plan, but pick up any features that are external only. Take note of any steps, ramps, changes in level and anything that won’t have been picked up from the internal survey. Again, take loads more photographs.
Taking photos for a measured survey
Usually after measuring either a room/area I then photograph the entire room – focusing on any difficult or complicated areas. I tend to take far too many photos but I’m sure it pays off. It is always a great help when you are back at your desk trying to draw up the scribbles. In some cases I would take a video of each room, which is quite useful as you can pause it to check any particular details. I sometimes find with photos, there is always one photo that you haven’t taken, and it’s always the one you need!
Take photos of the outside of the property from various angles and if necessary from down the street too. Depending on the reason for your survey, sometimes photos from a distance can be useful for planning, or perhaps for creating a street view visual of the proposed plans. Once you have returned from the site, make sure you sort your photos into folders, ie, inside, outside, by room etc. It makes life much easier when you are drawing up the plans to be able to quickly find a photo for reference.
One method we use to measure angles of strange shaped buildings is triangulation.
The image above shows how to carry out this method. Pick a point on one wall (A) and measure to the corner. Pick a point on the second wall (B) and measure to the corner. Finally, measure the distance between the two points on the wall (C). This will give you the measurements of all three sides of the triangle. From this you can either work out the angles, or draw it up in cad more easily.
I have also written another article about measuring angled walls – check it out here.
If you come across an area that is technical or difficult to present in your drawing, I sometimes draw it at a large scale and cross reference it. This allows you to create a more detailed sketch of the difficult area to refer back to.
Try to ensure your laser is as level as possible when taking measurements. If you need to take smaller measurements, it is often better to use a tape measure so make sure you have one to hand.
Try not to rush the measured survey. I have been on surveys when the building is cold, dark and pretty spooky, and I wanted to get finished as quickly as possible. The problem is, by rushing it you will undoubtedly miss crucial details and possibly have to return at a later date.
Be particularly careful on site when you are working alone on your measured survey, especially if you are in old or unstable buildings, working in loft spaces etc. Use your judgement on what is safe to survey. Take spare batteries for your laser, just in case they run out mid survey.
When measuring external information, be sure to take note of site boundaries, and any neighbouring property information that might be useful.
Measured Survey Checklist & Guide
We have put together a comprehensive measured survey checklist that you can use when you visit a site to carry out a measured survey. Along with the checklist, you can get access to this guide too as a handy PDF.
Just hit the download button below!
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We also have lots of other survey related content. Be sure to check it out:
I hope this post helps you when you have to carry out your measured surveys.
If you have any other useful tips – please feel free to share them in the comments below.