Hardrow Harmonies

Hardrow Harmonies

Subtle individual blend of "mixed colour" designs, unique to Hardrow for a unique, vibrant aesthetic. 

Hardrow Slates have been, and continue to be, a favoured choice for a range of roofing applications.

View our brochure for more details.

William Davis Homes case study - using Forticrete Cast Stone and Forticrete Hardrow Overture roof riles
Hardrow Harmonies

Subtle individual blend of "mixed colour" designs, unique to Hardrow for a unique, vibrant aesthetic. 

Hardrow Slates have been, and continue to be, a favoured choice for a range of roofing applications.

View our brochure for more details.

Please fill in the form below to request a printed version of this product's brochure, alternatively download an e-version on our Resources section.

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Can I install a conventional roof light with Forticrete Roof Tiles?

In most cases there is a suitable conventional roof light flashing kit which can be used with our products down to a roof pitch of 15 degrees. Forticrete would not recommend the installation of a conventional roof light below 15 degrees with profiled tiles.

Conventional roof lights when fitted below 15 degrees under certain weather conditions my seep water over flashing. Forticrete have a Low Pitch Roof Window solution, which when used with Forticrete Centurion tiles can be used at a pitch as low as 10 degrees.

Do I need to ventilate my roof if I am using a breathable underlay?

Ventilation and control of ventilation is covered under BS 5250: (Code of Practice for control of Condensation in Buildings).

General information relating to traditional cold roof spaces

Breathable underlays work by transferring moisture laden air from inside the building into the batten cavity (the area between the top of the underlay and the underside of the tiles) where it is allowed to ventilate out between the gaps in the roof tiles or slates.

The gaps in between the tiles or slates will vary depending on the manufacturer and therefore additional ventilation may be required at the eaves or ridge line to assist in drawing the air in the batten cavity out of the roof.

Condensation forming on the back of the roof covering without adequate batten cavity ventilation may result 'Lime Staining' on the face of the tile.

In Forticrete's opinion additional ventilation should be provided at high level in the form of a ventilated ridge line. If the selected tile is flat additional ventilation should be used at the eaves.

Please consult with the tile, and underlay manufacturer for further advice.

General information relating to Warm Roof Spaces

Where the insulation is positioned between and on top of the rafter to the appropriate insulation level and is fully sealed is known as a warm roof. 

In this instance no additional ventilation is required.

How many tiles are required for my roof?

Forticrete can provide a free take off service for roof areas in excess of 60m2 which will give an estimate of how many tiles and fittings you will need to order.

It is important that you fully specify what tiles, fittings and ventilation you require by filling in all parts of the estimate request form which is available as a word document or pdf format.

Side elevations and roof plans will be required with dimensions clearly marked on them.

All estimates are given as a guide that should be checked prior to ordering as any extra costs incurred due to over or under ordering will not be covered by Forticrete.

Please allow up to fifteen working days for return.

Site specific fixing specifications in line with BS5534 should be obtained prior to installation. You can request a fixing specification by visiting myforticreteroof.co.uk.

How many tiles per m²?

The number of tiles per m² will depend on the type used and in certain circumstances the pitch. The table below shows the number of tiles per m² for all Forticrete roof tiles.

How much ventilation do I need for my roof?

For duo pitch roofs over 15º and below 35º an eaves ventilation of 10,000mm/m² is required when the insulation is placed at ceiling level and 25,000mm/m² when the insulation is inclined to the rafters. For roof pitches over 35º or where the span across the gable end is greater than 10m, 5,000mm/m² high level ventilation is required.

For mono pitch roofs over 15º the eaves requirements are the same as for duo pitch roofs but high level ventilation is required at all pitches.

For all roof types below 15º the eaves ventilation requirement is 25,000mm/m².

I have a roof pitch that is below the minimum recommended pitch for your tile. Is there anything that can be done?

Our roof tiles have been designed to perform down to their respective minimum pitches.

Below these pitches concrete tiles become purely decorative, and require a secondary waterproof barrier to be employed to carry any water down to the eaves and effectively discharge into the gutter.

There are several manufactures' that provide corrugated sheeting systems but these will always raise the overall height of the roof.

Otherwise a marine plywood deck can be installed with counter battens.

Apertures created in flat sub roof sheeting will have to be fully sealed around the up stands to allow water behind the opening to discharge around it.

Apertures cut into corrugated sub roof systems are not allowed as water in the corrugations above the junction will be trapped.

For further information please call the Technical Department on 01525 244900.

I have been told I can hang Hardrow slates. What is hanging and can it be done?

Tile Hanging - (suitable for roof pitches up to 40 degrees).

Hardow Slates are manufactured without hanging nibs, and require two aluminium 40 x 3.35mm nails per slate to be tapped through the nail holes positions allowing them to be hung over the top of the 25x50mm graded treated batten.

(Aluminium nails should be substituted for copper or stainless steel in marine environments)

All hung slates are to be mechanically fixed at the verges (including roof lights, chimneys, and open valleys) by double battening over the top of the parent batten which is fixed across at least two rafters.

Two courses of slates at the eaves (including the under eaves) and the top course of slates including the top slates under the ridge should be directly fixed into the tile batten.

Roofs located in areas of severe wind speeds are to a fully nailed into the batten regardless of tile pitch and verge slates secured with additional verge clips.

What angle of Hardrow Ridge is suitable for my Roof pitch?

The table below outlines the 5 different Hardrow Angle Ridges that are available and the roof pitch range that these are suitable with.

What batten spacing should I be using for my tile?

Please refer to the specific product details within the website for individual product information relating to batten spacing.

What distance does my first batten need to be up the roof?

The values below are based on the distance from the front of the fascia to the top of the batten with the exception of Hardrow and the Concrete Plain Tiles. The distances for these are based on the front of the fascia to the centre of the batten.

Double Lap Tiles such as Hardrow and Plain Tiles use an Undereaves Tile (often shortened to Eaves Tile), and the batten distance is given for these as well.

What distance does my last batten need to be from the top of the roof?

The values below are based on the approximate distance from the top of the roof to the top of the batten.

Double Lap Tiles such as Hardrow and Plain Tiles use a Tops Tile. The batten for this usually sits on edge underneath the top of the last course of tiles, and the Tops Tiles nail into this. The quantities below are based on the last course of tile rather than to the tops course.

What height does my fascia need to be above the truss end?

The ventilated figures below assume that Forticrete's Eaves System is being used, which has a tray for supporting the underlay behind the Fascia. If an alternative form of ventilation is being used, the figure should be reduced by 6mm to allow for a 6mm plywood fillet to support the underlay.

What quantity of batten do I need when using Hardrow slates?

The quantity of batten required will depend on the slate size and the gauge at which they are laid. The table below outlines the quantity required:

What size of nails do I need for fixing my tiles?

The following table outlines the size of nail required to fix each of the Forticrete Roof Tiles:

What size of tiling batten should I use?

With truss or rafter spacing up to 450mm a 38x25mm batten should be used, spans greater than 450mm up to 600mm 50x25mm batten should be used. If concrete plain tiles are being used, 38x25mm batten can be used up to 600mm spacing.

When are ¾ tiles used?

The use of ¾ tile are used primarily for achieving the broken bond in the Gemini tile only and are used on a verge or a side abutment only. The ¾ tiles are not used on a hip or valley.

Which lead detail should I use at side abutments?

For flat profile interlocking tiles the recommended method of protecting a roof/wall junction is to install a continuous cover flashing and a secret gutter. With profiled interlocking tiles the recommendation is to provide a continuous cover flashing in lengths not greater than 1.5m.