Articles about Construction:

FOUNDATIONS
PRESERVING TIMBER IN TIMBER FRAME BUILDING
Rendalath Wall System
ROOF TRUSSED RAFTERS
TIMBER FRAME EXPLAINED
TIMBER FRAME HOUSE PROCEDURE
WHAT ARE ECO-JOISTS AND TRUSSED RAFTERS?
WHAT IS BIOCONSTRUCTION
WHAT IS A U-VALUE AND WHAT DOES W/m2K MEAN?

FOUNDATIONS

Foundations are the starting point in construction and a foundation transmits the building spread-load onto the earth.There are many different types of foundations designed to deal with differing earth conditions and types of buildings occupying the foundation. Each of the following classification are also sub-divided to allow a certain use.

Strip Foundations
Shallow Foundations
Raft Foundation
Pad Foundation
Piled Foundations

At the moment we only need concern ourselves with “Shallow Foundations” and one particular one at that – The Raft.

Shallow foundations are those founded near to the finished ground surface; generally where the founding depth (Df) is less than the width of the footing and less than 3m. These are not strict rules, but merely guidelines: basically, if surface loading or other surface conditions will affect the bearing capacity of a foundation it is 'shallow'. Shallow foundations (sometimes called 'spread footings') These include Pads (“isolated footings”) strip footings and RAFTS

Shallows foundations are used when surface soils are sufficiently strong and stiff to support the imposed loads; they are generally unsuitable in weak or highly compressible soils, such as poorly compacted fill, peat, recent lacustrine and alluvial deposits, etc.

Raft foundations are used to spread the load from a structure over a large area, normally the entire area of the structure. They are used when column loads or other structural loads are close together and individual pad foundations would interact. A raft foundation normally consists of a concrete slab, which extends over the entire loaded area. It may be stiffened by ribs or beams incorporated into the foundation. Raft foundations have the advantage of reducing differential settlements as the concrete slab resists differential movements between loading positions. They are often needed on soft or loose soils with low bearing capacity as they can spread the loads over a larger area.

The raft excavation should be a minimum of 60mm wider and longer than the proposed buildings footprint in all directions.

The raft should be excavated to a minimum of 600mm and filled with compacted MOT (Hardcore).

This should be blinded over with sand or ash and a DPC membrane overlaid.

The fill should then be overlaid again with re-enforcing mesh raised on concrete cups.

A shuttering of 150m should be constructed and a specified concrete design mix poured to level, and vibrated to remove any air pockets.

go Top

PRESERVING TIMBER IN TIMBER FRAME BUILDINGs

There are basically two types of preservatives used in our industry known simply as "In Ground" or "Above Ground".

In both cases the timber should go through a Vac-Vac treatment and this is what happens:

Milled planks of timber are placed in a treatment vessel.
A vacuum pulls the air out of the wood and the vessel
Osmose preservative is then flooded into the vessel
The vessel is then pressurised, forcing the preservation fluid into the timber
The preservative fluid is removed and a final vacuum is applied sucking out all excess fluid.
The timber has now been Vacuum impregnated

In Ground Applications:

A copper base is used in preserving fluids for in ground external applications. Alkaline copper quaternary systems have been in use over 10 years now all over the world, very successfully on Fencing, Timber Decking, Landscaping and Playground Equipment.

Above Ground:

A borate base is used mainly, and protects against: Wood boring Insect and Fungal Decay. Is used on both internal and weather protected external timbers above ground.

Note: CAA (chromate copper arsenate) is now illegal in most countries because of its carcinogenic implications. All formulations which have replaced CAA MUST meet full European Standards BS8417

Attack Resistant to:

Ground Termites
Formosan Termites
Carpenter Ants
Woodboring Insects ( Inc. Anobium and Xestobium)

After treatment ALL timbers must be kiln-dried (KDAT) to a maximum moisture content of:
19% Timber and 18% Board/Sheet materials.

Typical Timbers to be used:
Southern Yellow Pine
Douglas Fir
Hem-Fir
Spruce-Pine-Fir (S-P-F) is mainly our classification in Timber Frames)

Standard:
Known as AWPA - C9 Plywwod - C31 Above ground ooc (out of contact with) P5 Environmental compliance

go Top

Rendalath Wall System

go Top

ROOF TRUSSED RAFTERS

Trussed Rafters or Roof Trusses are without doubt the most popular way to form roof scapes. Not only do they arrive on site as a fully engineered and certified product, they are considerably cheaper and much more versatile than a traditional “cut roof” and typically consume 40% less wood. Trusses supplied by Timber Engineering Europe are made in our factory from drawings prepared by our engineer specifiers. We take your house drawings and special truss design software is used to determine exactly what is required in each individual case. Once our design engineer is satisfied that the chosen calculations meet all the necessary regulations he will issue the approvals.

There are many different types of roof trusses known as Duopitch type or Monopitch type. This simply means Duopitch has two slopes and a central ridge, whereas Monopitch has only one slope and sometimes called “lean-to”.

The most common Duopitch are shown below with the average span, although greater spans can be achieved.

1. King Post Truss	Spans up to 4.5m	Uses: House & Garage Roofs
2. Queen Post Truss	Spans up to 6.0m	Uses: Usually Domestic
3. Fink Truss	Spans up to 11m	Uses: Most common and takes water tank
4. Double W	Spans up to 16m	Uses: Commercial and Futuristic
5. Howe Girder	Spans up to 8.0m	Uses: Supports other Trusses & loose infill

The most common Monopitch are shown below with the average span, although greater spans can be achieved.

1. Mono 2/1	Spans up to 2.5m	Uses: Hip Ends and Lean-to Roofs
2. Mono 2/2	Spans up to 4.5m	Uses: Large Hips & Span on to Firewalls
3. Mono 3/2	Spans up to 6.0m	Uses: Back-to-Back Central Corridor
4. Mono 3/3	Spans up to 8.0m	Uses: On Monopitch Roofs

The timbers permitted for use MUST be stressed graded usually TR26 and C16. Most of the timbers used in Truss manufacturing are from Europe, Canada and Britain. The common species are BS.5268: part 3
Whitewood and Redwood – Europe

Hem-Fir	Canada & USA
Douglas Fir-Larch	Canada & USA
Spruce-Pine-Fir	Canada
Southern Pine	USA
Scots Pine	UK
Corsican Pine	UK

Moisture: BS5268: Part 2 Stipulates that the moisture content of any timber must not exceed 18% although BSEN14250 does permit the moisture content to be 22% at manufacture provided will be dry to below the 18% value during construction.

Trussed Rafters are primarily made up of Tension and Compression members.
A tension force is a pulling or stretching force, like a tow rope and a compression force is being pushed or compressed, like a table leg of a support column.

So, if you look at a typical Duopitch Fink Truss configuration the Bottom Chord is a Tension Member and the two “Roof Slopes” are Compression Members. The two outer infill members are in Compression and the two inner members (stretching from apex to bottom chord) are in Tension. There are 7 pieces of wood joined together with a “pull and push” type relationship as 4 pieces are in Compression and the other 3 are in Tension.

Some roof designs require a mixture of different types of Trusses, which make them so popular, almost any shape and size of roof can be achieved using Trusses although in some cases, depending on the design of the building some alternative support such as Steel or Glulam Beams may be called for.

The use of RIR (Room in Roof) attic trusses are becoming very popular, as around 60% of the ground floor area can be utilised as living space at very little extra cost on new builds. In a new- build or a restoration, 60m2 could be added to a 100m build, at little cost, and the sale value of the property increases quite considerably.

go Top

TIMBER FRAME EXPLAINED

TIMBER FRAME BUILDING

There is a great deal of confusion concerning this modern method of construction and in many instances, Wooden Houses, Log Cabins and Garden Buildings are mistaken for Timber Frame – they are not.

WHAT IS TIMBER FRAME?

Timber Frame Construction is exactly what it implies. It is the “bones” of a building. Just like the human skeleton, it is extremely strong and supports everything inside it and has an outside skin, usually brick, stone or render. The timber frame is an engineered solution and replaces the almost redundant internal load-bearing block wall.

HOW DO YOU KNOW IF A BUILDING IS TIMBER FRAME?

The short answer is “You don’t”. Timber Frame buildings look exactly like any other except that they have many, many more advantages over old traditional methods of construction. (Benefits are explained later). Timber Frame can be anything from a small home extension to a 7 floor high block of apartments or a school building to a 300-bedroom hotel. In fact ANY building can be constructed using this technology.

ARE THE HOUSES ALL STANDARD DESIGNS?

No, none of them are, each property is bespoke and designed to the client’s own specifications. On receipt of planning drawings we then undertake engineering calculations, and each individual project is re-designed taking into account many different factors including site location, wind speeds over a long period, snow-loadings, building heights, elevations and geographic information and so forth. Using these complicated formulae we then produce drawings for manufacture and site erecting, which is all part of the service we provide.

go Top

TIMBER FRAME HOUSE PROCEDURE

The Construction of a Timber Frame House is quite simple and can be broken down into modules as follows:

GROUNDWORKS
TIMBER FRAME
ROOF
WINDOWS & DOORS
INSULATION & PLASTERBOARD
PLASTERING
PLUMBING
ELECTRICS
JOINERY
KITCHEN
TILING – PAINTING
EXTERNALS

The Groundwork consists of excavating drain runs, service trenches and foundations. Next the drains/services are laid but not connected. Next, strip foundation is concreted and the Bricklayer will bring the load-bearing brick/block walls to DPC. All is then backfilled, and the site levelled.

Once the slab is complete and an allowance has been made for the services/utilities in and out, the timber frame is erected by Timber Engineering Europe. This consists of External Walls, Internal Walls, 1st floor joists and decking, plus roof trusses.

Next we call for the roofer to complete the roof-scape.

Then the External doors and the windows go in, we now have a sealed envelope, so internal works can commence, irrespective of what may be happening outside (bad weather – lack of bricks, Building Inspector can’t make it, or whatever reason)

On completion of this stage, the Electrician & Plumber are called in to 1st Fix. This means all the pipe work and cables which will carry power and water are run through eco-joists and into the stud wall voids. Nothing is connected at this stage.

Immediately the joiner moves in to 1st fix Stairs, Door Frames, and Window Linings. May install floating floor on Slab. External Fascias & Soffits.

Once complete, the plasterer moves in to insulate between the studs and joists. He then boards the ceilings and walls internally and skims the boards or prepares for a dry-line finish, which accepts a paint coat. May float ground floor to Slab.

The Bricklayer by this time will have commenced on the outside skin, or if this is to be rendered, the Plasterer moves from inside on completion of the plastering, to commence render on exterior.

Joiner returns to final fix doors, skirts and architraves, along with the Tiler. The Kitchen Fitter will appear at this stage.

Electrician returns to do final fix - lights and power sockets, wire up any machinery make connections.

Plumber returns to do final fix – install and connect all White ware, Heating, Soils & Wastes. Makes mains connections.

On completion of the above, the Painters start.

Any externals quoted for e.g. Paths, Fences, Landscaping. Last is snagging and final inspections, prior to handover

go Top

WHAT ARE ECO-JOISTS AND TRUSSED RAFTERS?

These are engineered load-bearing components used in our kits. Details are shown on separate pages. We can also supply both components as stand alone items for those restoring properties.

go Top

WHAT IS BIOCONSTRUCTION

The term “Bioconstruction” is being used more and more in the construction industry. Last week we heard from a company in Spain who build “concrete meat lockers” and claimed that their products were a Bioconstruction. If you are considering building or buying, and you want a Bioconstruction, your new home should fit into the basic guidelines as follows:

Integration into the environment
Meeting sustainable codes
Use of natural, healthy materials
Self-sufficiency in energy and optimisation of resources.
Treatment and recovery of waste.
Geobiology
Costs

The above is the overview and general consensus of agreement of what “ Eco-construction” means in respect of a new-build. From a pedants standpoint the term “Bio-construction” refers to the natural build-up of mineral solids underwater, such as reefs, and is in fact a borrowed word used to persuade others that a product is ecologically superior to another. I suppose it could be argued that as reefs are made from particles including lime and so is concrete, then it is Bioconstructed, (it probably takes just as long anyway!) So you can see how misleading the term is and how it can be adapted then adopted to suit.
Bioconstruction obviously can’t be achieved by one operation in construction and as Bioconstruction does not have any set codes, standards or regulating bodies in Spain or Portugal it therefore can’t be classed as a method of construction. (See UK Sustainable Codes in Construction)

Timber Frame construction is accepted globally as a major component of Bio-construction, as it allows a building to breathe but is of little use if the rest of the operations required to complete the project do not meet the criteria. Therefore it is necessary to have an agreed programme, method and material agreement prior to construction.

Iberian traditional methods of construction using concrete and steel can never be considered as anything other than an outdated and particularly undesirable method in this day and age.
Bioconstruction calls for natural, healthy, replenish-able, primary materials, allowing respiration of buildings and preventing unwanted unhealthy interiors. Timber Frame Construction meets all these provisions – Concrete fails on all these provisions.

Our aversion to quarry products is well known and we have posted various facts and figures concerning its undesirability in our world, but leave you with this one:

Every year the amount of concrete manufactured equals 1 cubic metre for every person on earth and China uses 40% of the total manufactured, and production is due to increase dramatically as the newly developing countries demand more.

Timber Engineering Europe

go Top

WHAT IS A U-VALUE AND WHAT DOES W/m2K MEAN?

A regular question we are asked is ‘What is a U value and what does W/m2K stand for’?

Right here we go:
A "U Value" is a measurement of how well a building component retains heat inside a building. For the Spanish contingent, this is equally important because the "U Value" is also used to determine how long the inside of a building can be kept cold.

In both cases "U Value" is needed to establish the amount of energy required to retain a comfortable interior temperature.

So, a "U Value" is a measure of the heat flow through a building element (e.g. Wall) The higher the U value the more heat you are loosing. Therefore the lower the "U Value" the better for us because we want to retain the preferred temperature.

How do we measure a “U Value”? Well, this is where our little mate the W/m2K comes into his own!
“U Value” describes how much thermal energy, expressed in WATTS (That’s the W) is transported through the building component the size of 1 SQUARE METRE (that’s your M2) at a temperature difference if 1 KELVIN (there is the K). The Kelvin is equal to 1 deg C. So, W/(m2K)

What do we need to achieve under the English Building Regulations Part L?
The law says a min of) 0.27W/m2K must be achieved.

What do we achieve with our 140mm stud system?
Depending on the insulation we use we can get down to almost ZERO emission.
We can therefore easily meet and beat minimum requirement, once again demonstrating that we have a very superior 140mm system compared to others, who only use an 89mm external stud. Ours is also an infinitely superior system to Brick/Block construction, as we exceed the target rating and still have a clear cavity for air circulation which Brick & Block do not have, because the cavity is stuffed to the gills with all sorts, to achieve the minimum rating of 0.29 Wm2K

We hope this has been of some use to you.
Timber Engineering Europe

go Top