MJ Rooney Construction Foundation Specialist
Foundations construction has been a specialty for groundworks contractor MJ Rooney Construction for 35 years. Basement foundations were our main type of groundwork back then. Now, MJ Rooney specializes in many types of foundations and will value engineers to find the best foundation construction for your project. Basement foundations are our main forte which may include basement underpinning and piled foundation.
How to Choose a Foundation for a House
There are many types of footing available when choosing a foundation for a house. Firstly, you must design based on the ground conditions, cost, safety and sustainability. Your Groundworks Contractor should tell you all of the types of footing available and the cost and advantages of each. Poor ground conditions will require deep foundations such as piled foundations or a raft foundation to spread the load over a wide area.
Types Of Foundation
Basement foundations are a specialty of MJ Rooney and would generally involve underpinning foundations below a house. Piled foundations or Reinforced Concrete superstructures are common to form a basement in the garden. MJ Rooney will value engineer the most cost-effective basement foundations for your project.
Guarantees for Foundations
MJ Rooney offers the best 10-year guarantees on the market with Insurance backed guarantees or full Latent Defect Insurance available. MJ Rooney is a member of ASUC (Association of Specialist Underpinning Contractors). We are therefore audited in technical and Health and Safety to the highest standards by independent assessors.
In-house Engineers will design foundations and Temporary Works for your Foundations construction project. MJ Rooney is a Groundworks Contractor with an eye for low-cost foundations construction combined with temporary works design. We can design many different types of footing and have a specially trained Groundworks team for all of the Foundations Construction listed below
General Types of Foundations
There are many different types of foundation, Choosing the right type for your site is dependent on a number of factors. Ground conditions need to be considered in a soil investigation report. The proximity of trees, watercourses, and sloping sites are also important. The load of the building must be safely transmitted to the ground and future additional loads should be considered. General types of foundation are:
- Trench Fill Foundation: Trench excavation filled with concrete.
- Strip Foundations: Trench excavation with bottom filled with
- Pad Foundations: Cuboid blocks of concrete taking loads from columns or ground beams.
- Raft Foundations: Flat reinforced concrete slab usually with a thickened perimeter.
- Underpinning Foundations: Concrete trench fill foundations made in small 1m sections.
- Piled Foundations: Usually deep columns of reinforced concrete.
- Drilled Shafts or Caissons: A watertight retaining structure for foundation forming.
- Diaphragm Walls: Structural concrete wall formed in the deep bentonite-filled trench.
There are many variations in each type of foundation. There are also foundations with a combination of different types of footing to make hybrid schemes.
Best Foundations for a House
The best foundations for a house will be the most cost-effective civil engineering solution we can get to support the building loads for the ground conditions and geology. This will take future loading, slope, and trees into consideration. Safety for the operatives, adjacent structures, and temporary works must be considered in the permanent works design. Sustainability and future demolition must also be taken into consideration. Safety for the operatives, adjacent structures, and temporary works must be considered in the permanent works design. Sustainability and future demolition must also be considered.
Basement Foundations form the walls of a basement while taking the load of the building to a lower level. The foundations take a vertical load of the building as well as the lateral load from the soil and groundwater. Reinforced concrete makes the best basement foundation construction as it resists the water entering the basement.
Retrofit Basement Construction
Retrofit basements are formed below existing houses and are usually made of reinforced concrete walls. Underpinning in 1.2-meter sections is usually used to form the basement foundations and link up to form a box resistant to water ingress. Foundations for a house formed in this way will need waterproofing before space is made into a habitable room.
Newbuild Basement Foundations Design
The type of foundation for a new-build house will be designed specifically for the site conditions In many projects the proximity of adjacent structures and the need for temporary works will be a major design consideration. If the basement excavation can be completely dug out with sloped battered sides then the basement slab is poured without temporary works propping in the way.
Basement Wall Foundations on a Battered Site
There will be no temporary works in the way and therefore the options for a basement wall foundation on a battered site are as follows.
- Reinforced Concrete wall with two-sided shuttering.
- Hollow concrete block such as Stepoc from Anderton Concrete.
- IFC Basement wall – insulated polystyrene blocks filled with concrete.
- Quetta Blockwork – concrete blockwork with concrete infill.
- Precast concrete wall sections like twin-wall filled with in-situ concrete
Basement Wall Foundations with Temporary Works
If temporary works are needed to hold up the ground while the basement is being constructed then walls of the basement can be built within a temporary work’s structure. Piling may be used to form the wall structure and temporary works at the same time. Usually, contiguous piling will have a reinforced concrete liner wall. If steel sheet piling or kingpost temporary works are used to support the ground then a reinforced concrete wall can be poured against it.
What are Trenchfill Foundations?
Trenchfill foundations are one of the most common types of footing for a house or wall. A groundworks contractor will excavate a trench usually with an excavator. The trench will require some temporary support works if operatives need to enter the trench or stand close to the edges. The trench will then be filled with concrete to make a foundation.
What are Strip Foundations?
Strip foundations are formed in the same way as trench-filled foundations but only a shallow fill of concrete is poured into the base. Once set the structure is then usually built up to DPC level with masonry brickwork, blockwork, or trench blocks. Strip foundations were used many years ago when concrete was more expensive and Labour was cheaper to build the walls. Also, the safety of operatives working in a trench to build the walls was not to a high standard like today. Generally, Strip foundations are avoided these days.
Piled Foundation Type
Piled Foundations for houses and basements are columns of concrete extending deep into the ground to transmit building loads to lower levels. Piles can transmit the loads via friction on the sides, end bearing, or a combination of the two. Piling can be used in a variety of ways to form foundations.
- Individual bored piles connected to a ground beam for a foundation.
- Individual bored piles in the base of pad foundations.
- Individual bored friction piles to prevent uplift in basements.
- As precast-driven piles in steel or concrete.
- To form a basement wall with contiguous piles.
- To form a basement wall with secant or interlocking piles.
- As mini-piling where there is limited access.
- With steel screw piles drilled into the ground
This is continuous flighted auger piling and can be used in conditions where the ground is not stable for open bore. The auger is driven deep into the ground and then concrete is pumped through the hollow stem of the auger. As the concrete is pumped the auger is withdrawn leaving a column of wet concrete. A circular reinforcement cage is then dropped into the wet concrete to make a reinforced concrete column. CFA piling can support individual loads or be drilled in a continuous line to form basement walls such as contiguous piling or secant piling.
Open Bore Piling
Open bore piling can be used in subsoils such as clay where the ground is capable of remaining open after the hole is bored. The auger is usually in short sections that are added on while the hole is bored to depth. The auger is then withdrawn and each section of the auger is removed to leave a completely open hole. The hole is checked to make sure it is clear of debris and then a steel reinforcement cage is dropped into the hole. Finally, the hole is filled with grout or concrete.
Mini piling is used where there is limited access in width or headroom. There are some very small mini-piling rigs that can fit through the doorway of a house.
Screw piling can be used where the loads to be supported are very light. Screw piling is also commonly used in ground stabilizing schemes.