Friday 29 October 2010

Construction Drawings?

When it comes to building new houses or extensions, Irish people often don't see the need for construction drawings or haven't in the past. I've experienced it myself in the past, where people go off and get prices or engage building contractors based on information contained on "planning permission only" drawings.

What's the difference. Everything really, planning drawings are not required to contain detailed information on construction, other than to convey the basic design and outline finishes, overall dimensions, location and position of opening etc. Atypical drawing which I would include as part of a planning submission is indicted below

Construction drawings by their nature should contain sufficient information for someone to build the dwelling/building from. The information contained on the drawings should enable works be undertaken in compliance with the building regulations; be it thickness or position of insulation, opening sections to windows, or size of the roof timbers or whatever. Furthermore, construction drawings allow the designer, to convey how s/he wishes specific element of the building be finished, eave overhangs, downpipe poisitions or even finishes. While much of the information relating to building regulations is standard (or was ), as most regulations don't regularly change, except for Part L, relating toConservation of Fuel and Energy (insulation in otherwords), many building contractors are not always familiar with other amenements.

Why not provide construction drawings at planning application stage? Well it can be done, however in terms of providing value for a client, its not the best route; in many instances, the house or development granted permission, varies from that applied for, often requiring amendments during the planning process, be it minor amendments or sometimes a substantial redesign or in cases the development has been refused permission.Furthermore planning authorities do not access development in terms of compliance with building regulations, their is to access compliance with the planning policy.

Of course one benefit of construction drawings, it it allows a building/dwelling be accurately priced, when prepared in conjunction with a relevant specification. The less information a building contractor has, the more assumptions s/he makes and the greater chance what s/he delivers is not what the client had in mind.

Wednesday 27 October 2010

Cottage renovation Part 4

The main roof structure is now complete, with work now progressing to preparing the roof for the velux windows. Velux windows to the south elevation will include vertical combinations, avoiding the necessity to construct dormers.
As noted below, rafters overhang the blockwork by a considerable amount, to allow for the provision of the external wall insulation, withthe insulation carried up  to the top of the wallplate, reducing cold bridging.

Wednesday 13 October 2010

Cottage renovation Part 3

An unscheduled site visit had to be made yesterday to sort out a few unexpected problems. Addressable, however they do delay the work.

Despite starting on Monday and joisting out the first floor, the carpernter are not expected on site agin until Friday. Flooring to the first floor with be 18mm ply, providing a good base for tiles and laminate floor finishes.

Thursday 7 October 2010

Cottage renovation Part 2

Work is progressing on the cottage renovation. The project is behind programme, not helped in this instance by Tipperary winning the All Ireland Hurling Final: direct labour projects by their nature seldom go according to programme, as one is at the mercy of the sub-contractors, many of whom know that it will be the one and only time they will encounter that individual self-builder, unlike working for a building contractor.

At this stage the blockwork is complete. There is some work required around the existing opes, however this work is underway, mainly comprising of adjusting the cill levels, tidying up around the location of the former heads. New heads were cast as part of the band beam at first floor level. Cold bridges normally caused by band beams have been avoided in this instance with the used of external insulation.

The carpenter is due early next week to complete the first floor and commence the roof. While this will be going on, the windows and doors will be ordered(black uPVC has been selected) and installed prior to the installation of the external insulation and render. The external wall u-values have been calculated at a respectable least 0.22W/m2 using a thickness of 120mmof EPS insulation.

Consideration is currently been given to insulating the roof space along the line of the rafter right up to the ridge, creating a warm roof. I’m currently looking at the prop and cons of this, one major advantage of this method, which the clients sees, is of course the risk of frozen water pipes or a water tank is greatly reduced. The fact that there shouldn’t be excessive temperate differences in the attic, compared to the rest of the house, both in winter and summer, is also another factor wish is attractive to the client. Cost however may prove prohibitive… Kingspan, Xtratherm, Aeroboard, anybody?