1.  Original unedited topographical survey (ideally as issued by the surveyors)

This survey shows the existing features and control stations on site, enabling the proposed works to be orientated to the site.

Formats required:

 a             Adobe Acrobat PDF for printing (.pdf)

Ideally this should be as issued by the topographic surveyors including their borders and legends so origin of grid and datum

can be assessed, this can save time on proof checks at the start of the project.

b             2d CAD (.dwg)

for overlaying, proof XY checks and control station co-ordinate extraction.

c             3d CAD (.dwg)

For volume calculations and cut/fill models for enabling works

2. Setting out plan for all plots.

This plan should show the position of all buildings. The dimensions of the plots shown are expected to correlate with the house packs for overall size and shape. The FFL of all plots, house type, whether it is handed or mirrored, and plot numbers should be shown. The drawing should show the topographic survey in the background to enable it to be referenced to the site. This plan is expected to be updated in line with any alterations in building sizes, including alterations due to change of wall thickness or similar. This plan is used to check house pack dimensions, it is expected that they will correlate.

Formats required:

a             Adobe Acrobat PDF (.pdf)

for printing and checking all Xrefs have been issued

b             2d or 3d CAD including all Xrefs (.dwg)

To enable dimension and co-ordinate extraction. It is expected that this drawing may be used for setting out.

3. House packs (inc. garages), block plans and soleplate layouts if timber frame.

These drawing provide the details of each house type to be built, we require all types including garages. It is expected that terraces and semi-detached houses (ie where plots are joined in blocks) are provided in a joined format (ie block plan) to ensure that all internal/external wall thickness are correct and overall dimensions are in line with the plots plan 2 above. So if the development has for example plots 20 to 25b as a terrace comprising of two “type A” 3 bedroom houses, one of which is handed or mirrored, two “type b” two bedroom houses and a ground floor and first floor flat “type c” at the end then it is expected that the individual types will have been combined by the Architect/Developer into a single block plan with the appropriate foundation and sole plate layouts etc.

Formats required:

a             Adobe Acrobat PDF (.pdf)

for printing and checking all Xrefs have been issued

b             2d CAD including all Xrefs (.dwg)

To check against site layout as described in 2 above. To overlay wall/foundation layouts to the plot setting out plan 2 to enable dimension

and co-ordinate extraction. To ensure sole plate drawings for example match overall dimensions etc. It is expected that these drawing

may be used for setting out.

4. Foundation layout (inc. retaining and screen walls) with associated detail

This should show all foundations to be built within the development including plots, retaining and screen walls. It is expected that this will align with all Architects and Engineers drawings. Top and bottom of concrete foundation level should be shown along with step locations (and step details) foundation width/depth and any local widening and offsets relative to the bearing wall line. Substructure foundations for plots are generally read in conjunction with house packs. It is expected that this plan reflects the current site layout and should overlay to plot layout plan 2 above.

If there are any piled foundations piles should be numbered and cut off level provided along with associate details such as depth, type, diameter, integration with ground beam/foundation etc. Drawing should show the location of the piles by either co-ordinates relative to the site grid (ie original topographic survey) or with figured dimensions relative to the walls of the house type or block plan as described in 3 above, to enable the location of piles to be co-ordinated to the site grid and hence set out.

 Retaining walls that are “standard details” and bespoke are expected to show the foundations widths/steps/levels as described above as are screen walls. They are expected to align with the current site layout, ie they should be updated in line with design development. Whilst it is not desirable it is often the case that retaining wall alignments are shown as single lines on site layouts with reference to a standard detail. In these cases, the construction team assume the line represents the exposed face of the wall, from which it is then necessary to apply the standard details to interpolate and deduce the substructure requirements. We consider this to be a task that should have been carried out by the design team as undue assumption and interpolation is required.

Formats required:

a             Adobe Acrobat PDF (.pdf)

For printing and checking revisions, notes/legends to check all Xrefs have been issued in CAD versions.

b             2d CAD including all Xrefs (.dwg)

To check against plot layout as described in 2 above. To overlay wall/foundation layouts to the plot setting out plan 2 to enable dimension and co-ordinate extraction. To ensure sole plate drawings for example match overall dimensions etc. These drawing contain important information regarding levels, width/depth and location it is therefore necessary and expected that these drawing may be used for setting out, they should correlate with all other construction drawings.

5. Infrastructure & External Works, (often termed engineering layout)

These drawings in CAD often contain a multitude of data and contain all the layout details for highways, paths, parking, drainage, kerbs, streetlights and the like. There are often numerous tabs within the CAD files that provide the paper space for various PDF drawings of for example streetlights, kerbs, surface finishes etc. These CAD plans are hence of great importance to the development.

 The levels and contours shown on these drawings are expected to show the finished surface level, or in the case of drainage the designed invert level and cover level. Intermediate layer levels eg underside of raised table/ramp, gardens pre-topsoil, kerb race, binder course level should not be shown. These intermediate layer levels are deduced from standard details relating to surface types. Many of the points listed below in 6 to 13 are contained within the CAD file of the engineering layout.

 Forrmats required:

a             Adobe Acrobat PDF (.pdf)

For printing and checking revisions, notes/legends to check all Xrefs have been issued in CAD versions.

b             2d or 3d CAD including all Xrefs (.dwg)

To check against plot layout as described in 2 above. To extract co-ordinates and level information for the various elements, to overlay as built and check surveys, to compile setting out sketches for operatives showing offsets and the like set out. Data is often extracted for ground modelling to enable volume calculations and machine control models.

6. Surfacing and kerbing plans.

These drawings should show the various kerb types and upstands along with the various surface types and finishes. For example, roads where a different construction makeup/depth is required should be indicated as well as any change of finished surface type. It is expected that these plans relate to the current site layout and the surface types and makes ups relate to the standard details.

 Formats required:

a            Abobe Acrobat PDF (.pdf)

for printing and checking revisions, notes/legends to check all Xrefs have been issued in CAD versions.

b             2d or 3d CAD including all Xrefs (.dwg)

These are often (but not always) incorporated in the Engineering Layout CAD plan, they may also be Xrefs of the Engineering layout. They are required in this format to extract co-ordinates, dimensions and positional information for the various elements, to extract quantities for orders, to overlay as built and check surveys, to compile setting out sketches for operatives showing offsets and the like set out.

7. Drainage, ponds, soakaways and schedules

It is expected that these drawings should show all of the various networks, foul and surface water, adopted and private. Outfalls to ponds and existing networks should be shown. The layout is often shown in the CAD file for the engineering layout noted in 5 above. It is exected that the plot and external works shown are to the current layout. The drawing is expected to show:

·         The position of each manhole along with the cover level and incoming and outgoing invert levels.

·         It should indicate any manholes that have a backdrop.

·         Each manhole should have an individual number that relates to the drainage schedule.

·         The pipe diameter and type of each run between manholes should be shown along with the direction of flow, it is common to also show the gradient of the run between manholes.

·         The various networks should be easily identifiable via legend and layering as to their type eg private/adopted etc.

·         Soakaways should show the size, base level, depth and incoming and outgoing invert levels and positions.

·         Ponds should show the finished base level, incoming and outgoing invert levels and location positions, headwall types, contained water side slopes, water level, interim berm levels and width, side slopes to original or proposed finished levels.

Manhole schedules are expected to be updated with design development, and it is expected that they show all manholes in each network. Each manhole should show:

·         MH ref no

·         Co-ordinate of the manhole on site grid as per 1 above

·         Depth to invert

·         Connecting pipes with orientation, invert and diameter

·         Manhole size, type and cover type

Formats required:

a             Abobe Acrobat PDF (.pdf)

for printing and checking revisions, notes/legends to check all Xrefs have been issued in CAD versions. MH schedules in PDF format only.

b             2d or 3d CAD including all Xrefs (.dwg)

These are often (but not always) incorporated in the Engineering Layout CAD plan, they may also be Xrefs of the Engineering layout. They are required in this format to extract co-ordinates, dimensions and positional information for the various elements, to extract quantities for orders, to overlay as built and check surveys, to compile setting out sketches for operatives showing offsets and the like set out, to compile machine control data/models.

c             3d strings in .dwg CAD format for ponds.

The top/bottom of batter strings in 3d .dwg format enable the creation of machine control models to enable accurate construction to quickly commence.

8. Highways

It is expected that these drawing should show the proposed finished road levels and contours including the finished levels of raised tables and ramps. Whilst the design process is typically horizontal alignment, vertical alignment, application of crossfalls and width the end product in the layout is expected to be finished contours at a suitable spacing typically 50mm. These contoured layouts provide the majority of the information to enable a residential estate road to be set out. The long sections and cross-sections that are often prepared at an earlier part of the design process and which adopting authorities often require to ensure compliance with design codes are not generally referenced for the computation of setting out data. These sections are expected to correlate with the finished levels and contours noted above on the highway layout. Road drainage including gullies are normally shown on the drainage drawings.

Formats required:

a             Abobe Acrobat PDF (.pdf)

for printing and checking revisions, notes/legends to check all Xrefs have been issued in CAD versions.

b             2d or 3d CAD including all Xrefs (.dwg)

These are often (but not always) incorporated in the Engineering Layout CAD plan, they may also be Xrefs of the Engineering layout. They are required in this format to extract co-ordinates, dimensions and positional information for the various elements, to extract quantities for orders, to overlay as built and check surveys, to compile setting out sketches for operatives showing offsets and the like set out.

c             3d strings in .dwg CAD format for roads.

The finished channel and centre lines in 3d .dwg format enable the creation of machine control models to enable accurate construction to quickly commence. It is expected that these strings correlate with the contoured road layout drawings and are finished levels incorporating table tops and ramps at finished level.

9. Service and other miscellaneous plans

9.1 Service layouts: There are a number of additional plans that dictate the groundwork construction. Service layouts enable the setting out of service routes. It is increasing necessary or advantageous for services or ducting to be installed in advance of kerbing or other reference elements and hence setting out of these routes is required. Whilst some services follow kerb lines many elements such as rising mains take bespoke routes. To enable services to be accurately constructed the route of each service and either its invert level or depth below finished level should be shown. If the depth below finished level is quoted it is expected that the finished level is easily deduced from the engineering layout (5 above) or highway layout (8 above). The service layout is expected to be shown with the current external works background. The service routes are not expected to clash with drainage routes or any other sub-structures or services and connection points to existing services should be shown. The location size and orientation of sub-stations including slab thickness and foundation details should be included and referenced to any standard details.

9.2 Street lighting and illuminated signage: like the service plans preparatory work is often required prior to kerbing and the like. It is expected that the layouts are prepared with the current engineering layout as a background.

9.3 Tree Protection fencing: One of the first tasks on many projects is to mark the tree protection fencing ahead of any works be undertaken. The drawing should show the route clearly, the background should incorporate the topographic survey 1 and a suitable site layout such as 2 or 5 above.

Formats required for the above:

a             Abobe Acrobat PDF (.pdf)

for printing and checking revisions, notes/legends to check all Xrefs have been issued in CAD versions.

b             2d or 3d CAD including all Xrefs (.dwg)

These are often (but not always) incorporated in the Engineering Layout CAD plan, they may also be Xrefs of the Engineering layout. They are required in this format to extract co-ordinates, dimensions and positional information for the various elements, to extract quantities for orders, to overlay as built and check surveys, to compile setting out sketches for operatives showing offsets and the like set out. Machine control models can be created from existing service routes or tree protection fencing that prevent an excavator from working within a defined zone and hence ensuring work is carried out safely.

10. Background to format types

CAD is computer aided design or draughting software such as AutoCAD, CivilCAD or BricsCAD to name but a few. It enables dimensions and co-ordinates to be deduced and extracted. Almost all PDF and paper plans are exports from CAD. If a PDF has been produced it should almost always be available in a CAD (.dwg) format.

Xrefs are individual CAD (.dwg) files that are linked to another CAD (.dwg) file that brings the numerous Xrefs together. For example, a highway drawing alone may be blank apart from the border and some notes, however it is made up of several Xrefs of say, kerbing, finished contours, line marking and signs. So, the highway drawing for a PDF in the above case is made up of the highway drawing in CAD along with the four additional Xrefs.

PDF plans are essentially produced for viewing and printing. If a dimension or label is not shown, then it cannot be readily deduced. PDF plans alone rarely show significant dimensional or positional information to enable setting out. PDF plans do however generally include drawing borders that should provide drawing titles, drawing numbers, revision information, legend/notes, originating company, date of issue and drawing status such as “for construction”. Much of this is of significance to those tasked with the construction of the development.

11. Data Control

As the drawings are required for construction purposes, it is expected that drawings that are provided are “For Construction”. Traditionally drawings are issued, and a drawing register is maintained. PDFs are invariably numbered, and the file name usually incorporates the drawing number and revision. It is extremely beneficial if the file name incorporates or at least alludes to the drawing title. It is extremely time consuming when looking for a specific drawing to be confronted with a list of files with no clues as to what they contain and so each one must be individually opened. CAD files and Xrefs in particular are not always as well named, and CAD files that are issued with names such as “drainage.dwg” can often not contain any other reference information regarding what drawing number it is or is part of, what revision it is etc. Our team carefully compile data as it is received however consideration of data control and file naming from originators is considered essential for the smooth management of the construction process.

Our teams are primarily responsible for the delivery of the groundworks element of the project. Bulk issuing of all drawings to us including roof truss detail, internal kitchen layouts and the like is not necessary and increases the burden on our teams to sift through these bulk issues.

Online portals are increasingly common and can be advantageous however we believe that data and drawing should be issued to the groundworks contractor, and it is their responsibility to distribute drawings to their suppliers. If a developer is using a portal, it is expected that the groundworks contractor is notified if any drawing revisions are uploaded, and these notifications should be for relevant drawings. As noted previously we are not interested in a change to the roof truss design, but we do want to know if the drainage has been revised. We do not consider it to be the responsibility of the contractor or setting out team to check a portal daily to see if drawings have been revised, relevant revisions are expected to be notified.

12. Basic setting out techniques

12.1 A robotic total station. Setting out is generally undertaken with a robotic total station. For the older generation this is essentially a remote-control theodolite that in addition to measuring angles also measures distances and has a computer onboard to do some of the maths. These instruments are most effective when working with co-ordinates and so the majority of setting out preparation involves the computation and extraction of co-ordinates. Some surveyors like to employ CAD drawing files on the instrument to compute the co-ordinates. Ultimately the instrument must be able to observe known survey control (survey stations from 1 above) to know where it is on the site. It then needs to be fed (via co-ordinates extracted from the data above) to enable it to calculate the angles and distances to the point to be marked. Good survey techniques enable points to be marked to mm accuracy. The loss of survey control stations dilutes the accuracy within the site and hence should be protected.

12.2 GPS or GNSS essentially uses similar on-board computing with co-ordinates as a total station to locate a point. The significant difference is that instead of observing control stations every time it is used it takes reference from satellites overhead. However, before the first time it is used on a site it is necessary to reference the control stations from the original topographic survey (1 above). This is to check whether the original survey is to the Ordnance Survey National Grid or a local grid. If it is to OS has the earths curvature been allowed for or has it been flattened, is a local calibration to the site control required. The GPS is computing its position based upon satellite positions using the World Geodetic System that we see as latitude and longitude. The surveyor and the supporting instrumentation needs to convert this system to the site survey grid from 1 above. Reputable survey firms will note this conversion and grid orientation in the border of their drawings and hence consultants removing this information and re-branding the drawings with their own title blocks often results in the loss of these important details.

GPS is not as accurate typically as a total station and accuracy of 20-50mm is more likely, so it is not suitable for use with blockwork for example. Whilst the total station needs to be able to see survey stations GPS needs to be able to see satellites and so a clear view of the sky is required. GPS generally fails to operate well or at all when close to, or under tree canopies or alongside high buildings. Generally, a mobile phone signal is required to enable corrections to be received, although a local base and radio solution can overcome this if necessary.

13. Machine Control

Machine control (MC) is now used extensively in residential developments. There are a number of types of machine control however the most commonly employed system is 3d GPS. The plant is ordinarily fitted with two GPS antenna that along with a series of sensors mounted to the booms of the machine connect to a controller in the cab that the driver can see. The team at Kemp are able to remotely upload 3d models that represent the element to be excavated. This enables a quicker turnaround of data from receipt to excavation than would normally be the case. The models could be for footings for a plot, formation for a road, a trench for a drain or the excavation of a pond.

With these models loaded the driver is able to see where the bucket of the machine is relative to the level and position of the model. The driver is able to apply offsets to the model also if necessary to allow for trench bedding or similar make up items. These systems are very efficient, they reduce setting out with pegs, improve accuracy (still limited by GPS as described in 12.2 above), they relieve the requirements for a banksman and enable the driver to obtain the required level quicker, saving time and fuel for the machine.

This technology is the future for the industry, and we have hence invested time and money in hardware and in developing workflows that see a return on this investment. The Kemp team are able to provide models that are suitable for all of the main machine control suppliers, Leica, Topcon and Trimble. Receiving design information and data in line with that described in this guide enables that efficiency to start earlier in the construction process and leads to a successful development.

14. Summary of drawings & formats                                                                                       

1. Topographic survey                                                       (.dwg & .pdf formats)

2. Plot layout/setting out                                                  (.dwg & .pdf formats)

3. House packs                                                                    (.dwg & .pdf formats)

4. Foundation layout                                                          (.dwg & .pdf formats)

5. External works                                                                 (.dwg & .pdf formats)

6. Surfacing & kerbing                                                       (.dwg & .pdf formats)

7. Drainage, ponds, soakaways and schedules    (.dwg & .pdf formats with 3d dwg strings for ponds)

8. Highways                                                                           (.dwg & .pdf formats with 3d dwg strings

for channel and centre lines)

9.Service & other miscellaneous plans                   (.dwg & .pdf formats)