Underpinning in Foundations

Underpinning in Foundations

Underpinning is a method used to increase the foundation depth. This may be done in case a developer wants to add more stories to a building or in case of damage to the foundation by tree roots and this, this can be used as a corrective application. Also the adjacent construction may have foundations lower than the existing thus requiring to be lowered or basements are constructed very near an existing building thus necessitating foundation change or cracks may appear in a building up to the base thus needing a foundation remedy. Foundation underpinning may be applied to deal with all the stated instances.

The underpinning in foundations is undertaken and supervised by an engineer. These works should follow instructions keenly for safety assurance. Before any commencement of work the area of operation should be hoarded. The area to work on is measured and mapped out. The work should commence from the corners working inwards. This is done on load bearing walls only. Foundations without any load bearing walls are exempted. The defects on these walls can be corrected using most simple methods.


The underpinning in foundations starts with excavations. This should be done under a strip footing. A pit measuring a length of a thousand millimeters, a width of five hundred millimeters and depth of five hundred millimeters is dug. This is distance between the pits should be two thousand millimeters. After the excavations, mass concrete is added to the cavity. Mixes are one part cement, three parts sand and six parts aggregates. Concrete is made to a good consistence and is poured into the cavity. Use form work on the edges. Use a rod bar ensuring that the cavity under the existing foundation is filled up.


After the underpinning concrete is placed in the cavity, it is allowed to set for two days. The operation is repeated for the next bay. This continues until the required foundation is complete. Ensure that the concrete is cured thoroughly before loading it. The next thing is to break off the projecting foundation. Cut the concrete flush with the mass concrete surface. After this is completed for all the bays, soil is then back filled and compacted thoroughly. Watering with a hose is done for consolidation of the soil.

Repairing Leaking Roofs

Repairing a Leaking Roof Valley

The rainy season is here with us and by the look of things I am convinced that it is not letting go soon. Which calls for some measures to be taken where our roofs are concerned. So today we look at ways of dealing with a leaking roof valley.

Leakage in a roof valley usually occurs due to weathered panels, pan tiles or flashing which are not working properly. In any of the cases, you will have to replace some of the panels, pan tiles or slabs to mend the leak. Before starting to replace the withered material you will have to analyze the panels or tiles properly. Here are some of the steps to be followed when repairing a leaking roof valley.

Step 1 –Take Necessary Measures
When repairing the roof from leakage, you may also use the tiles or panels which are exactly the same as your previous panels or tiles. You should always chose thick, good quality tiles and panels. The pry bar should be used very smoothly; if you apply too much pressure with the pry bar, you may break additional panels or even the roof. This will end up in you having to make additional repairs. Proper placement of nails is extremely important so do not put the nails on the junction area. Make sure the nails are not too close to the roof valley since they may cause strain on the panels or tiles and hence they may break more easily.

Step 2 – Taking off the Withered Panels or Tiles
Now pull the withered panels that easily come off the roof. If the other good panels are surrounded by some withered panels, then you need to pull off the withered panels by uplifting the edges of the good panels or tiles. If the tiles or panels are fixed with the help of nails, you may use a pry bar to pop out the nails.

Step 3 – Placing the Flashing
Now place the metal flashing in its place and bend the edge of the flashing in a way so that it forms a corral which is about 25mm wide. The purpose of creating a corral is to ensure the flow of water, and the enclosure shape of the corral will enable water to easily flow down to the drain.

Step 4 – Finishing Up

Now, adjust the new panels in the valley area in such a way that they should be placed in the same direction as the already placed panels. The edges of the new panels may overlap the older ones, and for correcting that, just lift up the edges and insert 2 roofing nails on each top corner of all the new panels. Next, insert the nails with the help of a hammer. To finish your work, just adjust the overlapped panels into their respective places on the top of the new panels.

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Ideal Orientation

ORIENTATION
If your home is oriented to take advantage of warm sun and cooling breezes, you'll achieve greater comfort at lower cost.

In general, ideal orientation means:
you get the right amount of sun - plenty in winter and in cooler climates, not too much in summer and in warmer climates
you're protected from strong/cold winds but can take advantage of breezes to cool your home when it is too warm.

When you're designing a home or planning renovations, there'll also be other considerations such as local climate, view, terrain, vegetation, street access and noise. You'll need to balance these against the benefits you can achieve through harnessing the sun's energy for heating and breezes for cooling.

Positioning for sun
To make the most of the sun for warmth and natural light, your home's main living areas (or any rooms you use a lot) should face north. The main glazing in the house, such as windows, skylights and glass doors, should also face north. Anywhere between 20ºW - 30ºE of true north is fine.

The exact amount of heat your home gets from the sun will depend on the season, time of day, weather, local climate and rate of air pollution. Heat is greatest when the sun is at a high angle relative to the horizon (i.e. it's higher at noon than at dawn or dusk). Heat is also greater in sunny than rainy or cold seasons.

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Building an External Stair For a Raised Ground Floor

Building an External Stair For a Raised Ground Floor.

An external staircase is used to access the raised ground floor. This floor is raised due to terrain or design. The steps are formed from the ground to the building floor. This stair is usually not a structural member and it is formed for access onto raised buildings, sloppy lawns and from embankments on a swimming pool deck. When forming the stair on heights greater than nine hundred millimeters, then a balustrade should be erected. 

Since external stairs is free standing it should have a foundation as this will make it stand firm and not sink. Finishing may be added depending on the desired effects. Most materials used include, concrete, stones, bricks, timber, steel sheets or tiles. The balustrades are constructed with steel or timber. The stair should end with a short landing. It is done at a hundred and fifty millimeters below the floor slab.

The external stairs are measured from the concrete slab edge. The height from the soil to the slab gives the number of treads and risers. A foundation is dug and concreted. The width of the stair should be about six hundred millimeters wide. A foundation wall is then erected for about two to three courses. The walls above the ground are then changed to medium dressed stones. The walls are stepped to form the stair. Hardcore is then added in between the walls.

The stones are laid raking backwards to the house. A stone is laid down first in a line. The next course starts two hundred millimeters from the end to form a step. This continues until the short landing is built. Below each course hardcore is poured and compacted. The balustrades are concreted from the ground upwards until they reach the house. Key pointing is fixed in between the joints to hold the stones together. Any desired finish is then laid over the stones for aesthetics.

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Making a Winding Staircase

Making a Winding Concrete Staircase

Winding staircases are usually constructed where the space is constricted. This is when a straight flight with a normal landing is not possible. The house design will have the upper floor with a normal height as for a straight flight stair. It is important that the head room is maintained as this will prevent hitting the upper floor slab with the head when walking up or down the stair well.

Winding concrete stair cases can be made to be economical on reinforcements and other materials. This does not need to have a full sized tread of nine hundred millimeters. The tread width can be four hundred and fifty millimeters wide and having a normal riser height. This height is usually minimum of a hundred and fifty millimeters high. The winding can be through three hundred and sixty degrees or less but this will greatly depend on the point of landing. The number of treads is eighteen including the landing.

The construction of a winding concrete stair commences by measuring the floor to floor headroom. The height of two thousand seven hundred millimeters headroom will give eighteen risers of a hundred and fifty millimeters each. Starter bars are first cast onto the ground floor slab. The intended width is four hundred and fifty millimeters wide. The form work is then made to the top of the upper floor and it is curved round up to the next floor. The height of each riser is marked onto the form sides. The reinforcements are then tied and joined with the exposed upper floor steel.

After the steel is in place, the riser form work is then fixed as marked while winding. This is repeated and adjustments done until all treads are equal to the top. Concrete is cast and vibrated. After fourteen days of curing the form work is removed and the finishing works begin . Winding handrails are fixed on both sides to the top for safety.

How to lay a roofing felt or underlay

How to lay a roofing felt or underlay

Roofing felts or underlays are fixed before laying roofing tiles or shingles. They are used underneath the final roof covers. Felts or underlays can be polythene or bituminous in nature. The reason for using them is to prevent any rain water from passing through to the ceiling as the tiles or shingle roof covers may allow water to seep through when broken. The placing of the felt or underlay should be done by a qualified carpenter and with due diligence the ceiling and entire house is protected from any roof leaks.

The roofing felt should be free from any punctures as these are likely points that water may pass through to the ceiling of the house. Sometimes when people want to adjust aerials on the roof they have to climb up the roof. This also applies when fixing digital satellite dishes or solar water systems and this increases the likelihood of disturbing the mortar on ridges or breaking a tile. It is essential that after works on the roof covers, a thorough inspection is done to check on damages. Any broken tiles should be replaced. The ridge tile and mortar should also be checked after any work is done on the roof surface.

The roof underlay or felt is purchased in rolls. When using polythene, it should be heavy gauge and preferably laid in two sheets. This is because the temperature in the roof space may rise thus leading to damages on the felt. The bituminous felt should preferably be the sand blasted type. This is able to take higher temperatures without breaking within the roof space. The felts should be laid smooth from the ridge to the eaves. This prevent them breaking after they become brittle during the cold season.

When laying a roofing felt, ensure the surface is horizontal and level. The roof structure is first completed then polythene is laid using plastic straps. The straps are nailed first on the purlins. They should be tight to prevent sagging under water weight. They are laid in a mesh pattern. After completion the polythene or felt is laid on top. The roof battens are then nailed onto the purlins and they are laid according to the tile specifications. The laying of tiles is then done after testing for sagging or any leaks within the felt.

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Roofing

Understanding various Roofing Styles and Slopes

There are many different roofing styles used today. Each style is unique in its structure and design, and often times to a particular location. A specific building type can also determine, at times, the type of roof that will cover it.

The reason that certain roofing styles are used in specific locations is because they all perform differently depending on the geography. This article outlines some of the most popular roofing styles used today, and provides some details about each one.

Hipped Roof
This type of roof characterized by four uniformly pitched (that is to say sloped) sides resembling a pyramid. Though not as commonly used as some of the other types, it can be seen in different parts of the world.

Simple Style Roof
With a simple style roof, all four sloping sides meet at a ridge across the top. Here, the front ridge is usually broader than the side sections.

Pyramidal Roof
On a pyramidal roof, all four sloping sides come to a point at the top of the roof. This, of course, forms a pyramid and is reminiscent of older architecture.

Cross-Hipped Roof
On a cross-hipped roof, perpendicular wings are added to the main section of roof, forming two individual sections both with their own hipped façade. A gambrel roof is constructed so that each side has two slopes; a steeper lower slope, and a flatter upper one. This is often associated with barns.

Mansard Roof
A Mansard roof forms a double slope where two slopes are located on each of the four sides. Here, the lower slopes are steeper than the upper ones.

Shed Roof
A shed roof consists of one high pitched planes covering the entire structure. It is often used for home additions and to cover porches.

Flat Roof
A flat roof contains no slopes, and may or may not have eaves. This type is still used in many locations today.

If you are in need of a new roof, and are unsure about what types and styles will work for your home or building, consult with a professional in the field.

Where you live can make a big difference, as well as the type of building you are wishing to re-roof. There are many options available to you and good professional to assist you in making this decision.

The cost of your new roof will also vary according to the type of roof you choose and materials used. Certain roofs are more complex than others and some materials cost more than others. The exact type you choose can be a matter of personal preference or can depend on location. Before you make a decision research all the types available to you to find out which will be best. Also ask about installation costs.

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