The difference between planning and construction drawings (Part 2)

I’ve blogged on this topic before but I think this post gives further clarification on the problem in Ireland (as I see it). It follows on from a tweet earlier today about working on someone else’s pathetic excuse for construction drawings (3 paragraphs of text and 10 dimensions) and the purpose of this post is to give clarification on what exactly is the difference between planning drawings and construction drawings:

Planning Drawings

The following are the key dimensional and material concerns regarding planning drawings:

You need to show overall dimensions ONLY in both plan and section; you don’t really need to give sizes of windows, doors etc…as the proportions once the overall dimensions are set can be seen from the elevations.

Regarding construction and materials; nothing regarding construction needs to be shown; the planners are only interested in the type of material and colour of the external surfaces such as walls and roofs.

Construction Drawings:

The construction drawings need to show a lot more information (and I mean a lot compared to what is commonly done by draughtsmen, engineers etc…). Every dimension in both plan and section of every single wall, opening, etc needs to be shown. Every aspect of the Building Regulations needs to be shown; the following is a list (not exhaustive) of common omissions:

Part A: Structure: Structural information is normally completely non existent.

Part B: Fire; Areas that need to be fire protected are not detailed sufficiently in terms of materials and fire door ratings

Part K: Stairs etc I don’t think I’ve seen many drawings with calculation checks over risers/Goings etc…- in fact I don’t think I see any information regarding how stairs are compliant

Part L: I’ve written a lot about non compliant insulation and air tightness standards – while I’m at it- I don’t think the majority of BER certificates are worth the paper they’re written on.

Part M: Disabled Access: Toilets cubicle frequently wrong size, level thresholds missing…

As I said this list isn’t exhaustive and I’m just touching the tip of the iceberg with the problems I see on a daily basis.

There are two questions therefore:

How does anything get built? Irish builders are a resourceful bunch. Left unattended they are excellent a making up dimensions, details and construction methods- sometimes correctly but oftentimes badly.

How therefore, has this situation developed?

Well in answer to the second question, the problem is the lack of understanding that the the planning and building control functions and requirements are separate. I frequently hear people say “my drawings are completely passed for construction” when what they mean is that the drawings have been given Planning Permission. As described above you need a LOT more information to build successfully from and as a proof that what you have drawn is firstly correct and then secondly that it has been constructed correctly. The drawing below shows just one of the dozen or so drawings that we created for a house extension.


So the norm (by draughtsmen & ‘engineers’) is that the drawings submitted for planning have the pathetic amount of construction information to make them ‘look’ like construction drawings whereas the have too much information for plannng and too little for construction. What we need to do is to look at the sums to see why this is so:

Let’s take a typical draughtsman price of a few thousand euro for a one-off house that includes the planning and construction information:

TOTAL COST OF DRAWINGS : €2000
Cost of land survey and percolation test: say €1200

That leaves €800 for the design, planning application and construction drawings. If you take the RIAI guidelines in the domestic agreement between Architect and Client and split the above fee into thirds you get a measly €266 per stage! How on earth can you get a considered design and a detailed set of construction drawings at this level ? The answer is you can’t unless you get a bog-standard design out of a book, drawings that contain too much detail for planning and too little detail to build from; which is the current situation when buying architectural services at his level.

CONCLUSION:

Nothing I’ve said here is probably new but at least it’s clarified in my mind the potential clients I need to work for. If you are looking for an ultra-cheap service described above then I’ll be happy to supply contact details of draughtsmen, ‘engineers’, retired woodwork teachers and a whole host of others providing ‘architect’ services. If instead you are looking for a registered architect that can work with you to provide a well considered and thoughtful design, negotiate with the planning authorities on your behalf, provide exceptional construction and tender information and finally to inspect and certify construction at the correct (and frequent) times through to completion then please CONTACT ME!

9 thoughts on “The difference between planning and construction drawings (Part 2)

  1. Simple and clear explanation. You could explain this to some University tutors, otherwise student are constantly guessing how much info should be shown on initial planning drawing and construction ones. No criteria is given.

  2. Great post Mark. I’d be interested to see your view on new Building Control drawings for SI 9 vs Construction drawings? Can there be any real difference in the two? Obviously we don’t need to show skirting and shadow gap details etc but surely the level of detail and spec is the one and the same?

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