How to Extend Your House

Tools You’ll Need

• Claw Hammer
• Lump Hammer  
• Sledge Hammer  
• KANGO Hammer
• Hand Saw         
• Skill Saw           
• Pad Saw (for cutting plaster boards/drywall)
• Shovel     
• Cement Mixer   
• A Meter Long Level   
• Trowel   
• 12m Measuring Tape  
• Handheld Concrete Float
• Spray Paint          
• String Line     
• Angle Grinder  
• Con Saw (for cutting through your path that surrounds your house)
• A Line Level  
• Drill  
• Plastering Trowel

Materials

• Concrete heads (for the windows and above the doors to keep the blocks that sit on top of the window openings)
• Sand
• Cement
• Blocks
• Bricks ( if your house is a brick house )
• Concrete ( order from a company )
• 2×1 (to hold the plaster board to the walls and the slates to the roof)
• 9×3 (for the roof and a bridge to float the concrete)
• 9×1 1/2 (used to finish the roof and hang the gutters on )
• Roof Tiles (for a better effect, get them to match the house)
• Roll Of Flashing Lead (don’t get the new tar stuff, it doesn’t last)
• Steel grids (2 for every 12 feet, to put in the floor to reinforce the concrete)
• Windows
• Door
• Window Sills
• Skimming Plaster
• Skimming Tape (for the joints in the plaster board)
• Gutter Piping Vis Screen (roll of plastic for under the concrete floor stops gases from entering your home)
• Rolls Of 13-inch Damp Course Joint Gutters (a small gutter object that slots into the joints between blocks to allow water escape)
• Insulation sheets for the walls and Rolls of Insulation For the roof
• Wall Ties
• Express Nails
• Hanger Ties (strips of steel with holes in them that keep the timber on the top the wall; they run from the outside of the wall over the top and nailed on, on the inside)
• Rolls of Felt (goes under the roof tiles)

Foundations

Take the Area of where you want to extend your house be it the whole length of the back of your house or just 10 or 12 feet of it. You will need the Measuring Tape and the Spray Paint, Lump Hammer, 2 Steel Pins (you can cut these off the steel grid) String Line

Measure the area where you want to come out from your house, Mark the wall of your house of where these points are by hammering a nail into it.. Measure out from these two points say its 12 feet and drive your steel pin into the ground at the 12 foot point on both sides. Get the string line and wrap the string from the nail on one side of you area around the two pins and to the other nail 12 up your house. This will give you the perfect lines you need for the foundations.

Spray the Spray Paint along the string marking the ground giving you a guide line for the foundations. You take the string away and you have the markings for the dig… You will need the shovel for this part because you will have to dig a trench along this line. This trench will have to be at least 15 inches wide and at least 1 ½ feet deep…

When this is done you will then need the Meter Long Level, Measuring Tape, Wooden Pegs ( you can make these from the 2×1 by cutting the two edges first to form a point then measure them 15 inches long you will need one for every meter in the foundations.

You will have to mark your house wall with another nail for the height of the foundation measure a foot up from your trench and drive a nail in on both sides. Using this nail measure a meter out into the trench and drive a peg checking that it is level you cut the pegs at 15inches giving you 3 inches to play with these pegs have to be the same level all the way around the trench meeting up with the opposite nail on the far side. Drive a steel pin in the two corners and get your String Line and your Line Level tying the string to the nail and level it off with the corner pins. This will able you to get an accurate level for all the pin. Pour the concrete into the trench using your shovel to spread it evenly across the top of the pegs… It all has to be one level. A meter and a half of concrete will do a twelve foot trench measurement don’t order more or you will be stuck with a bid rock in your garden.

When this is done and it is all level you will have to wait for it to go off.

The next day you start the 13inch block work on top of that make sure you do at least five courses of blocks. Build up the corners first squaring them from the house run your string and build your foundations, when this is done wait for the next day and allow the cement to set in the block work.

The mix of the blockwork is 1 bag of cement to 4 bags of sand. Same for shovels (1 : 4)

When these are set start levelling off the ground inside the floor filling it with the soil you took from digging the trench leave the top four to six inches short of the block work for the concrete to be poured. When this is level get your Vis Screen down let it over hang on all sides for the wall you build on top is going to seal the gas trap. Radon gas is highly dangerous make sure you get the required plastic for this case.

When the plastic is down cut 2 inch blocks off the 2×1 use these to prop the steel mesh above the plastic pour the concrete in you will need 2 meters of concrete form the company you got the other concrete from this will speed up the process. Tell them what its for when you call they will advise you on the concrete to use different parts of the world have different requirements.

When the concrete is in and filled up to the block work, you will have to get the shovel to even it out, stab a piece of 2×1 about a meter long with the shovel and use it to tamper on the surface or the concrete to get the water to the top. Get your make shift bridge built over the wet concrete because you will have to float it off to put a smooth surface on the top. Make sure it is all finished off properly if it looks done then it is done. Let it go off should take two days to set properly.

Walls

The Damp Course runs under the block work on top of the floor this is used if any water gets into your wall it will just run out side instead of in on your floor you will also need the Joint Gutters put into your first course of block work. Two blocks on edge for the walls tying them with wall ties and leaving a gap for the insulation between them. As you did with the foundations build up the corners first and run your walls into them. Leave a gap for a door and make sure you have the location where you want the windows. Always get the windows first because it is easier to build around the window than it is to get a window to fit an opening.

Windows are usually four courses of blocks off the surface of the floor but where ever you want them is fine too as long as you know the measurement for them. The 13inch Concrete Heads span over these openings and close the window gap. Build up to about 10 feet all the way around. The walls are done for now.

Roof

When you have built up the walls turn to the house wall and measure up 12 feet all the way across the wall this is where your wall plate is going to go. The wall plate must span the whole length of the area and take the weight of the roof . This wall plate is 9×3 that is expressed nailed to the wall you will have to use an 8mm drill bit and use a 10mm express nail. Drill through the timber into the wall making sure it is level from one end to the other. You have the wall plate up you have to run timber along the top of your adjacent wall holding them in place with the Hanger Ties. To get the angle of your roof you will have to hold a length of 9×3 13 feet long up to see where you will have to cut it at both ends. You will have to cut it at the top to sit on the wall plate on the house and then at the bottom to suit the wall and over hang 4 Inches… When you have the first one cut use it as a template to do the rest.. You will need one every 16 inches. Always put one on either side of the gable walls.

Nail them all up in the right places marking 16 inches along the wall plates on both walls make sure they are on the same side of 16 inches or you will have a crooked roof, and will have to start again. When this is done build up the walls on either side to meet the roof. When this step is complete you have to Felt the roof with the rolls of felt and hold them down with the 2×1’s spacing them 11 inches apart with a double 2×1 at the top of the roof, to suit the roof slate. When you have this done start slating the roof from the bottom up nail every second slate down so the wind doesn’t lift them, nail every one on the top row of slates.

Get your Lead Flashing and grinder and cut a straight line along the wall of your house about two inches deep and hang your flashing over the first slate on your roof. When this is done install your window sills and windows and doors filling in around the edges with expanding foam cutting the excess off flushing it with the window itself.

When this is done fill the gap with sand and cement as a reveal see your existing house window for how to do this because there are different ways these can be done.

Plaster the outside walls if it is not brick and let it go off while this goes off you can work on the inside.

Inside

Before you put up the dry wall you must fix 2×1 onto the wall every 400mm apart for plaster boards that are 1600mm wide. This will give you the perfect centres for hanging the dry wall always double up on doorways windows and corners so you have something to nail them to. If you want to have plug sockets and lights you must get an trained electrician now so you can hide all the wires behind the walls and ceiling.

When he is finished start hanging the drywall do the walls first and then the ceiling putting the joint tape on every joint. When this is complete just plaster the inside the instructions are on the bag of skimming plaster. Wait a week before painting and let it dry out completely or it will drink your paint. You can use this time to work outside and finish off the outside .

Outside

The gap has to be filled between the slates and roof with sand and cement mixed… you can buy dye to mix in with it to match the tile if you like… The facia board has to be attached on the over hang of the roof. In order for this to be right the roof beams all have to be the same length use a chalk line to mark them exactly, cut them all and fix the 9×1 ½ to the ends spanning the whole length of the extended rooms. Attach the gutter to this with the hooks that they sit on, put in your down pipe and marvel at what you just accomplished your finished out here.

All that’s left is to install a wooden floor and paint the walls – job done.