IGC Rooflights - FAQs

Frequently-asked questions

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I cannot find a cost for the size of the rooflight I require in the basic price list on the internet?

Please call or email your external frame/kerb sizes for an exact costing and confirmation that we will manufacture to fit over your external kerb size, please be sure to include roof coverings eg:lead, sana felt in your external kerb dimensions, we will apply a 5mm tolerance all round to fit over the external kerb dim you give us. Please note the price on the website are the external dimensions of the rooflight as shown on our drawing.

Why do you require payment in advance?

We make rooflights to customer specific sizes and work on tight margins and as such we require payment in full before materials are cut or glass ordered. We are able to take payment by internet transfer.

What delivery can I expect?

Slimglaze units are made in batches each month. Lead times can vary either way pending workload and clients should check circumstances during placement of order. General lead times are 2 -3 weeks from receipt of payment.

Do Slimglaze Rooflights comply with building regulations?

The rooflight uses a high insulating glass unit which conforms to Document L Insulation values of the current building regulations. Current building regulations state that the upstand must protrude at least 150mm above the finished roof surface and are typically made of timber.

In our experience most situations will comply without an issue. We advise all clients to check with their Building Control Officer on full compliance relevant to their particular installation.

Anglian Architectural cannot carry out building checks for each installation, this responsibility therefore has to be with the customer or their builder.

What is the U value of the rooflights?

The centre pane U value of the double glazed units are typically 1.1W/m2K and triple glazed typically 0.6W/m2K. As glass industry convention this reading is taken with glass in the vertical position when glass is moved to the horizontal it loses approximately a further 0.8W/m2K on the vertical value. This is true of all rooflight applications. The effect on heat loss of this difference is very minimal.

Can I walk on the rooflight?

No any standard rooflight is not designed to be walked on. If you require the rooflight to be load bearing please refer to our Walk on rooflights on the web site and request a price for your size.

Can I walk on a Walk On Rooflight?

Yes - Walk on rooflights are exactly that but it’s not such a silly question as it sounds. Standard units are designed to hold the walking weight of one 15 stone person or less and in most cases is designed to withstand a breakthrough if someone falls onto a rooflight for eg in snow conditions as being non fragile compared to the standard thinner glass used in a standard rooflight. Please note: specification of your requirements is key here. Walk on rooflights do not have the loading of a glass floor which require calculations to your sizes and specification of the loads you want the unit to take. Glass floors will normally have an anti slip screen print pattern on the glass, if you require a glass floor then send sketches and details for our review/costing.

Are the rooflights difficult to install?

No, anyone with simple DIY skills can install the Slimglaze Rooflight once you have your kerb prepared and flat (see attached drawing) it really is just a matter of lifting into place and screwing the unit down. (On older style SG1 style T section rooflights, a silicon seal or mastic joint is required.) The only tools you need are a battery drill, (mastic gun for SG1) and a screw driver. Contractors who do wish to apply a sealant to the kerb before screwing the rooflight to it - for eg: if you have a slightly uneven or old kerb then we can supply Low modulus silicone and screw fixings as a fixing kit available at a nominal cost of £12.00 per unit, excluding vat. Adshead Radcliffe have confirmed that their Arbosil Low Modulus silicone is compatible for sealing against roofing felt, lead, Sarna Membrane, zinc and neoprene. Please note the customer must check compatibility between any silicone/mastic used and their roof covering with their roof contractor - Anglian Architectural cannot offer this service or guarantee compatibility with other roofing materials but if you need to query your covering then call us and ask for the rooflight department.

What is the cost of delivery?

Delivery is by dedicated van and is charged at £1.55 per mile to you from our factory in Great Massingham in Norfolk.

Collection from our factory incurs no charge but is strictly Monday to Friday 9.00am to 4.00pm

An alternative collection point for London customers is located in Anchor and Hope Lane, Charlton SE7 7SQ. There may be a small charge for collection from this address for some sizes, contact rooflight sales for details.

Do the rooflights require a pitch?

We recommend a minimum pitch of 5 degrees to shed water off the Rooflight and eliminate rain water 'ponding' on the glass. For larger size rooflights 2 metres plus then 10 degree pitch will achieve better waterflow over the glass.

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