Home extensions

An extension is a promise that a new piece of building will behave as one structure with the old piece. The new room, the extra floor, or the wing has to meet the old foundations, the old roof, and the old drains without creating a crack at the joint or a waterfall where the two roofs touch. That is harder than starting on an empty plot, and it is why a cheap “just add a floor” offer is the sentence this page exists to slow down.

Households in these cities extend for ordinary reasons. A Lagos duplex in Ajah needs another bedroom. An Abuja house in Jabi wants a larger kitchen and a store. An Ibadan compound in Akobo or Jericho adds a wing for parents, or a boys’ quarters that was always talked about and never drawn. Sometimes the extension is vertical: a bungalow becomes a storey, or a two-floor house grows a third. Vertical work is where people get hurt, and where cities have seen buildings fail after floors were added beyond what was approved or what the frame could carry.

The old house has to be understood first

Before anyone prices concrete, someone competent has to say what the existing building is. Are the columns reinforced concrete or is the upper floor sitting on block walls? Were the foundations dug for one floor and then asked, years later, to carry two? Is there a drawing, and does the drawing match the building? In a city where houses are often altered by a different crew each time a child gets married, the honest answer is sometimes “we do not know yet”. That answer is allowed. Pretending is not.

A soil story still matters, because the new footings sit in the same ground as the old ones. On the Lagos coast, shallow groundwater and sandy ground can make a new strip footing next to an old one a settlement problem. In parts of Abuja the ground may be lateritic or shallow and stiff, which is a different excavation. In Ibadan, an extension toward a stream setback is not only a structural question. Oyo State has removed buildings from floodplains along the Ogunpa system, the Ona, and streams at Agbowo, Apete, and Challenge. Adding a room into that setback is how a family investment becomes a marked structure.

Load path is the phrase to keep. A new floor puts weight through columns into foundations. If you remove a wall downstairs to “open the parlour” at the same time, you may be removing the thing that was carrying the new weight. The engineer’s drawing is the document that says which walls may go and which new beam replaces them. A mason’s confidence is not that document.

The joint is where extensions fail

Water enters at the place the new roof meets the old one, at a balcony that was not given a fall, and at a slab that bridges over an old window head. In Lagos, June rain will find that joint. The August lull is not a promise that September will be kind; published averages show the rain returning strongly after the lighter month. In Abuja, a flat deck added over an old pitched roof, or a new parapet that traps water, fails in the long wet season from May through October. In Ibadan, a short violent storm — the city has recorded events on the scale of the August 2011 downpour — does not forgive a gutter that discharges into the foundation of the original house.

The programme should say whether the household can move out for the weeks the roof is open. If they cannot, the extension has to be built so the old rooms stay dry at the end of every work day. That costs time. It is one of the reasons two extensions with the same floor area do not cost the same.

Papers before blocks

Lagos defines an extension as a vertical or horizontal addition. Planning permission for the added area is a LASPPPA matter, and building control then wants notice, drawings, and, for taller work, insurance and soil information as the regulations describe. The FCT development-control manual is where height, setback, and use are checked; adding a floor that the district does not allow will not become allowed because the blocks are already on site. Oyo State asks for drawings and a site analysis before work, and the state’s own portal has spoken of a processing time in working days that you should confirm rather than treat as a guarantee. None of those systems publish a single fee on this website, because the charge depends on the proposal. Read extensions and approvals for the comparison, then use the quote form to describe the house you already have.

Send photos of each elevation, the place you want to add, and any crack in the old structure. Say how many floors exist today and how many you want after. Micheletti Construction Limited reviews that request. If the right answer is “do not build up”, that answer is more valuable than a price.