Understand Buildings - understandbuildings.co.uk

Glass Walls – Support, Spider Fixings & Mastic

Understood — Tue, 23 Mar 2010 14:01:10 +0000

When creating a glazed wall, curtain walling is one solution (with prefabricated sections hung in place) or, alternatively, the glass itself can be hung from a frame. Using trusses to span a wall or building height, often along with diagonal bracing, the structure must be strong in tension but able to flex if struck by wind.

Glass is often held by a four-point ‘spider’. This is fastened to the frame and has four fixings coming from it, positioned to connect to four corners of 4 different pieces of glass coming together at one point. A bolt holds the glass in place, and is surrounded by a rubber washer or ‘grommet’ that absorbs movement when the glass expands or contracts and is also weather proof.

The gaps between sheets of glass must be filled with a mastic which can stretch when glass contracts yet can be compressed when glass expands to maintain a weatherproof skin and prevent damage to the glass.

Tall Buildings – Construction and Services

Understood — Tue, 23 Mar 2010 10:11:50 +0000

Skyscraper buildings are usually built by constructing a core column in the building that is load bearing and is the main support for the construction. On the core, the various floors are effectively ‘hung’ from that support and then curtain walling techniques are often used to clad the exterior.

When in use, this core also is used to contain all main service provisions. It will include the stairs, lifts, electrical and information systems, cabling, water, toilets and fire facilities. This keeps all services neatly together and provides a larger, undisturbed area for occupiers.

Hardcore – Purpose and Content

Understood — Mon, 22 Mar 2010 16:08:48 +0000

Purpose

ensures uniform loading over ground
eliminates capillary void for damp
enables fill to required level
clean dry and level working surface

Includes…

brick/tile, clinker, gravel, quarry
waste, shale

Must not include…

plaster, timber, thermal block

Curtain Walling – Materials, Process, Uses, Insulation

Understood — Mon, 22 Mar 2010 15:04:46 +0000

Curtain Walling is a method of cladding a building using prefabricated materials that are brought to site and simply hung off the main structure. Often these skins are either profile steel sheeting, such as is seen on light industrial buildings, or glazed panels, such as on tall office buildings.

The process is very simple to do, and can be a very fast solution to cladding a building. The panels are not load bearing and can come in a range of sizes from a couple of metres square to, effectively, a whole, intact wall. An angled section on the back of panels simply hangs off the steel or concrete frame of the building and is fixed by a slot bolt which allows for left- and right-ward movement through heat change but keeps the panel fastened to the structure.

Glazed panels have columns and horizontal rails (as with standard windows’ mullions and transoms) as well as a ‘spandrel panel’ that is an insulated panel below the glazing.

Curtain walls also often have ‘thermal brakes’ at the joints between panels to prevent heat passing through the structure into the atmosphere, with associated problems of condensation, heat loss and stress on the building materials. Insulation is also usually built into the panels before they arrive on site.

Plan of Works – Part 2 – Design, Tender, Construction & Handover

Understood — Mon, 22 Mar 2010 14:08:28 +0000

<< Go back to Plan of Works – Part 1

Design Detail

This stage requires an agreement by all concerned of the design, in order for full drawings to be made as well as a complete cost check on all parts and components, pulled together in the Bill of Quantities.

Tender

Developers will then usually offer the project out to tender, inviting between 3 and 6 contractors to bid for the work. Once tender prices have been received it is the developers decision on which to choose, with many factors being taken into account, not just those on cost.

Construction

Pre-construction planning will occur to decide on strategy, security, storage and organising plant and labour, before a Programme of Works is drawn up to detail the co-ordination of all parties, how they will communication and co-operate, as well as inspections, supervisions and a schedule of payments.

Completion

Finally, on completion the contractors hand over the building to the developer. Usually a ‘defects liability period’ is written into the contract, and the contractor remains liable for repairs for a specified period. Finally, all outstanding payments will be settled and the building will be, hopefully, put into its intended use.

Plan of Works – Part 1 – Inception, Feasibility & Outline Proposals

Understood — Mon, 22 Mar 2010 14:08:03 +0000

When constructing a new building there is a standard pathway through the process, known as the ‘Plan of Work’. This is a series of steps through which the process must pass on its way from inception to completion. By understanding this series of steps, an appreciation for the construction process can be developed.

Inception

All projects must start with an idea, perhaps the result of a specific need, ambition or investment opportunity. Whatever the intention of the idea, one must be conceived in the first instance for the project to begin.

Resulting from the need, ambition or other stimuli, requirements for the building will become apparent. Decisions on what it should be for, where it should be and how it is to be paid for should be considered at this early stage, although no definite decisions are yet required.

The main question is what to build. A brief is usually drawn up, and a balance found what is desired and what can actually be achieved in terms of planning, physical design limits, functionality and cost. Other performance requirements such as weather exclusion, IT, fire performance and health and safety are usually also considered.

Feasibility

The sum of these discussions is to appraise the feasibility of the project for the client. This can often involve many professionals including a designer, architect, quantity surveyor and building surveyor.

Outline Proposals

From the inception and feasibility stages a rough, but hopefully clear, picture of what is required can be drawn. Initial plans can be drawn up and consulted upon as well as other tests like a User Requirements Survey.

As this stage progresses towards a finalised plan, requirements for Planning Permission and building control regulations should be applied for from the Local Planning Authority as well as the full preparation of a cost plan and appropriate discussions with lenders or financial backers.

Continue to read Plan of Works – Part 2 >>

Insulation – Thermal Advantage & Future

Understood — Tue, 12 Jan 2010 16:01:58 +0000

Insulation has the benefits of increased thermal advantage in a building. It locks in heat or helps to keep it out under warmer temperatures. It is also likely to reduce energy requirements, and as such utility bills and CO₂ usage.

Many consider it to be very cost effective with the pay-back-period often quite short with the cost savings developed.

In the future the development of very thick walls, of up to 0.5m, is likely.

Residential Building Heat Loss Areas

Understood — Mon, 11 Jan 2010 11:02:04 +0000

The main purpose of insulation is to reduce the loss of heat through a building. By looking at which areas loose the most heat from a domestic dwelling, key areas for insulation can be identified.

The following give an illustration of approximate heat loss percentages…

Roof – 25%
Roofs are now largely insulated to some extent to reduce this figure.

Walls – 35%
While cavity walls are now in many cases being insulated, for Victorian solid walls it can be difficult. Insulation will need to be applied internally or externally, with the later option often being unavailable as it is likely to change the external appearance.

Floor – 15%
This is often not considered but around 15% of heat is conducted through the floor and into the ground. More modern buildings are now insulating against this.

Doors – 15%
Primarily through draughts and ill-fitting doors, this can often be easily solved by fitting a draught strip.

Windows – 10%
Either through ill-fitting draughts or single glazing windows can loose a building’s heat. Double glazing is now common with some properties even having triple glazing. New developments such as ‘Aero Gel’ create a transparent walling material with the same thermal performance as a fully insulated wall.

Insulation Types – Loose Fill, Bat and Blanket

Understood — Fri, 08 Jan 2010 10:01:22 +0000

General insulation for walls or roofs can come in a variety of formats…

Loose Fill is made up of polystyrene beads or cellulose fibre and can be poured into spaces such as cavities.

Bat insulation is a semi-rigid insulation board often made up from compressed cellulose fibre, mineral wool or glass fibre.

Blanket insulation is very common and is, for example, used around hot water tanks. It is basically a mineral / glass fibre quilt.

Vapour Control in Timber Buildings

Understood — Thu, 07 Jan 2010 13:58:12 +0000

It used to be commonplace to have a Vapour Control Layer (VCL) as part of the wall lining in timber buildings. It would stop vapour escaping from rooms and into the structure, where it may condense and cause rot to occur – especially in timber framed buildings. More modern timber buildings, however, have their structure treated against rot so removing the need for a VCL as vapour is allowed to escape.