Conservatory Base and Walls

You’ll find below the basic details you’ll need to know about building the sub structure for the conservatory, covering excavation of site and footings, slab base and walls. If you are contracting your own builder then we’ll produce a base plan and measurements for him to follow. Normally we won’ manufacture anything until we’re satisfied the base works are correct as we obviously want (and so do you) a perfect fit for the superstructure. On excavation of your site. the builder may well discover unknown obstacles and slight alterations to a base layout plan may be called for. We also expect quality builders to be very accurate in their brickwork or build work. “Builder’s tolerances” may be necessary where plus or minus 5mm here and there may seem insignificant and, in truth, probably easily overcome by us at the fitting stage; but we’d still like a perfect fit for the superstructure. Striving for excellence after all, is no bad thing. A myriad of designs are possible with approaches coping with house wall shapes/features. There is usually a solution to what may seem a difficult site. Stone built, brick and rendered finishes are quite standard. We have access to structural engineers for roof loadings etc and have created and completed some pretty excellent build projects over many years.


Building the walls and slab base for your conservatory

The construction will be built in accordance with good building practice and building regulations/standards — and we often exceed them anyway. Most constructions require some or all of the following: – Clear site of soil/lawn or existing patio/decking. – Dig out and form foundation trenches. Conservatory salesmen in general are rather good at pointing out that “our company goes to 1 mtr deep foundations and more than our competitors”. This is a little wide of the mark (frankly it’s “sales speak”) and the better rule of thumb is that you should go down to load bearing sub soil and an extra 100mm for good measure. Therefore building near the Malverns for example in Worcestershire you’ll probably hit rock not too far down (the Malverns are extinct volcanoes after all) – sometimes just inches down. In the Severn Vale however it’ll probably be good old clay and perhaps shale/gravel under that. All situations will be different. Many old houses in fact often stand on maybe just 400mm of so called foundations and have been happily erect for hundreds of years. We often have the case therefore where our conservatory is built much better than the house to which it attaches! In summary then, we may well go deeper than 1000mm or less as soil and site conditions or building regulations dictate.

– Pour the concrete foundations. We would normally want to ensure the width of the cavity wall plus 100mm shoulders each side. Aiming for a 300mm deep wall construction then means a footing width of about 500mm. Depending on whether you have underfloor heating or not determines the actual layers constructed to make up the floor slab. However ¡t will be fully insulated and damp proofed using a membrane sheet. Screed top is the normal intent but again this depends on your final floor finish and possible underfloor heating cable system. Our web page on Underfloor Heating will go into this in further detail.
– Dwarf walls or other conservatory walls around 300mm thickness (inside to outside) can be brick inside and outside or brick and block (for plastering inside) or using stone of various kinds — e.g. Bradstone or even natural local stone. The walls are always insulated. Natural stone walls will often need to be thicker overall than 260 mm. – Drainage will either mean tapping into your existing systems or the construction of a soakaway pit to take away the rainwater runoff.
– Plastering inside all or some of the walls is an option as is rendering the outside wall area – usually to match the house finish. It is usual that skirting boards are also applied after plastering.
– Electrics are also catered for and we will agree the number and positions for double sockets and also interior conservatory lights. Most conservatory designs will allow a ridge light to be installed but conservatories generally look much better when lit at low level such as with wall lights and/or using table or floor lamps. Our electrician will install all items and provide the switch/es necessary for the lighting and will fit/mount the lighting fitting too — provided that the customer has the light fitting on site at the time of his visit; if not a call back charge will be payable. Our quotations do not provide for the actual decorative lighting unit of course.

Other items that may be needed:

– Internal manholes or drains can be dealt with by raising and sealing these items. However their cover/s will be visible inside the conservatory of course and it ¡s necessary that access is possible at all times in case you need to open up the rodding eye, manhole or drain gulley. Tiling is normally not a problem as the tiles can be cut around the covers and often tiles can be placed inside special tray layouts of covers. In this case you would then see only the frame outline of the cover – Demolishing of any existing structure and perhaps its old base is also often undertaken. We remove all spoil and demolished items from site and these are processed through a waste transfer station. Where possible items are used in recycling schemes and sending to landfill avoided where possible. – Cutting out brickwork from say an existing window or doorway is quite usual to form a new entrance way to the conservatory from the house. Lintel work can also be undertaken to form openings but this will involve the local Building Control Official and additional fees will be payable to the Local Authority for those aspects. It is usual to maintain an exterior quality door or doors once this opening is achieved. Open access is possible but again Building Control is involved and the main focus is on heat retention for the house and therefore energy reports (SAP report) is usually required and the specification of the conservatory tends to be higher (e.g. argon gas filled double glazing units as a minimum).

– The builder can also provide a full tiling or timber flooring service (engineered timber or laminate).
– Electrical fused spurs may be required for such things like underf loor heating systems and also weatherproof external power sockets can be fitted to the outside walls of the conservatory.
– Cooker and other extractor vents can be redirected so that they do not exhaust into the conservatory.
– Overflow pipes from upper floor bathrooms or toilets can either be re-directed if they end up inside the proposed conservatory roof area or a new modern siphon system for the toilet installed which negates the need for an overflow pipe.

– If your existing house has air ducts in the walls to vent the underfloor area in the main house, then these can be extended or piped under the conservatory floor to maintain the integrity of the existing air ducts.
– Radiators can be installed in conservatories if desired and a few notes here on that: Many people are misinformed over the building regulation rules. (Some conservatory salesmen either through ignorance, their own misinformation or the desire for them “not to get involved” to avoid the hassle of dealing with it all.. .will tell the householder that it’s not allowed in conservatories). The general rule of thumb is yes you can install a radiator but it must be able to be isolated from the main house system to which it connects. Basically it’s therefore fitted with a valve which can allow it to be shut off from the main house system.

General Points:

All spoil and waste will be removed from site and disposed off ethically and with environmental concerns to the fore. In fact most waste products (even from builder excavations), under new Government rules, have to go via appointed waste transfer stations where any recycling possibilities are covered. As a last resort does the waste go to landfill nowadays.

Sometimes (such as with mid terrace houses) we have to “go through the house”. Although this adds to the overall build cost — more so on the base construction aspects, it is quite possible to do this. The pathway through the house is often boarded up and sheeted with polythene to protect the house and its contents so that materials required can be brought into the back garden area. Concrete for base slabs can also be pumped through to difficult to access sites. If the customer requires other works done at the same time as the conservatory itself then the builder appointed can give additional quotations for that work. This usually involves maybe relaying patio areas, forming pathways around the sides of the conservatory or creating garden retaining walls. If the build area is either dropping away or garden area too high then either a build up or an excavation process is needed. This will be quoted for after the builder has assessed the area. We also sometimes use “block and beam” construction techniques where having an otherwise overly thick concrete slab is not feasible, cost effective or actually desirable. Also the main house floor level may be much higher than outside ground level and so this block and beam construction approach is a useful method to adopt. The system is very common these days and in fact with prices having become reasonable on the products required it is almost as cheap to build in this way rather than the “poured concrete slab” system. It’s a faster build and labour/time costs are reduced accordingly.