New roof
Don’t forget to check out our new flat roof replacement guide also.
Roof contractor
This guide will tell you what questions you should be asking you roofing contractor when looking for a new roof. I have not only been fitting new roofs for over 30 years but repairing them also, often shoddy workmanship is to blame but this can also be compounded by a lack of understanding on what to ask a potential roofing contractor by the customer or homeowner. Ignorance is not bliss… Ignorance is ignorance, and it’s costly.
Lets face it you wouldn’t buy a new car from a salesman in a show room based on colour alone would you, or if you didn’t know how many doors or wheels you wanted? No that would be silly, but a new roof will cost you quite a bit of your hard earned money and If you know what questions to ask for it just might stop you buying an overpriced crap roof. Blunt but true.
New roof advice
Before thinking of any new roof replacement there are some things you really should consider first, so please take a moment to read this guide on what to look for in a new roof so you can get a good quality new roof at a competitive and fair price from a reputable roofing contractor. Below I have listed the top ten questions I would ask a roofer about a potential new roof.
Top 10 questions to ask a roofing contractor about you new roof…
- Can you check my roof structure inside to check it is sound.
- What is the condition of my current roof and can I reuse the Slate or Tiles if I want to, If so what percentage do you think is reusable.
- Will my new roofs weight have a negative impact on the strength of my roof structure.
- Do I require planning consent.
- How will you join to my neighbours roof. ( if applicable )
- Will you be replacing valleys and flashings if so what with.
- Do I need or do you recommend roof ventilation.
- On roof pitches below 30 degrees, what undersarking and roof covering do you recommend.
- How long have you been in business, what is the guarantee and what does the guarantee cover me for.
- Are you Insured to work on my property.
How to ask roofing questions
Obviously standing in front of a roofer firing off questions one after another could make you look like a nutter, any tradesman now and again can get rouge customers who are a pain to work for. You don’t want to appear like a rouge customer so allow the roofing contractor to offer up as much of this information as possible during normal conversation, if you appear friendly and approachable many of these point will come up anyway during normal conversation. Listen to what he’s saying and steer the conversation towards items that may interest you. Most good tradesman like a customer to be interested in their work and the quality of the finish, they normally take pride in it so like to be asked.
Roof covering choices
From new the most common choices in the UK are… Concrete tiles, Slates – both real and man made, and Fired clay tiles. New tiles and slates often come with a manufacturers or merchants guarantee that is additional to the guarantee of craftsmanship and fitting by you chosen roofing contractor.
Common roof tile and slate manufacturers are Redland , Marley , Sandtoft , Forticrete and Dreadnought.
Re using your existing slates or tiles
If your existing roof has Slate, Clay tiles or Handmade clay tiles it can be an option to re-use and re-lay them onto your new roof if they are in good condition. This can be very desirable to keep the period look of a property whilst still achieving a new guaranteed roof with a lifespan of 80 years or over.
Re using slates
Natural Slate – Slates are the most common roofing material to be re used, get your would be roofing contractors to check and assess the condition of the slate for splits and quality. It is quite common to get a reusable figure of around 70% for the slate already nailed to your roof as long and there is nothing wrong with it, obviously this will be a cost saving on materials for you the customer.
Any missing slates can be purchased by yourself or the roofer from a roofing merchant in his reclamation section, second hand slates reclaimed from re roofs is a busy and thriving market.
Re using clay tiles
Clay tiles – Fired clay tiles, hand made or machine made can also be used again depending on condition. Things to look for are softness or flaking. Flaking is normally evident on the top surface of the tile or they can look like scabs of tile that fall down the roof. Tile softness or brittleness mostly only affects the handmade tiles.
Again get a roofer to check the condition of the tiles for viability, but if you have been luck to get a well fired good batch in the first place, there is no reason they cannot be used again.
Re using concrete roof tiles
Concrete tiles – Unless they are relatively new and in good condition, do not re use concrete roof tiles especially if older that 20 years. Concrete tiles are a great roof covering when new but wear thin with the passage of time and weathering becoming brittle.
Unfortunately weathering to the top surface of a concrete tile over is first few decades of life leave it open to moss, lichen build up or surface abrasion. It’s very questionable economy to spend a lot on money re-using a part worn product.
Roof structure
Make sure that the roofing contractors check the internal timber structure of your roof, this is to make sure that there are no problems that need to be addressed like roof sag, roof spread or incorrectly supported roof purlins. This is especially true in traditionally constructed roofs, and it is comparatively cheap to fix roof problems like this when the roof is stripped and ready for re-roofing rather than after the event. Also if you are considering a heavier roof covering like swapping from a slate roof to concrete tiles, make sure no additional support timbers or upgrades are required otherwise you roof may acquire sag or spread later.
Roof timbers – Unsupported roof purlins, just one example of a easy to fix problem that could need be addressed before the new roof goes on.
Roof pitch or roof angle
Every roof covering has a minimum pitch or slope unless its a flat roof. If you have a shallow pitched roof i.e. below 30 degrees of slope, consideration will have to be made on the type of roof covering that you are going to use. Commonly roof tiles will allow for a shallower pitch, sometimes as low as 12.5 degrees for certain makes of roof tile as against 20 – 22.5 degrees for selected slates. I have seen a lot of people come unstuck with leaking shallow pitched roofs, not only do you need the slate or tile to match the pitch but it also needs the correct amount of overlap and good undersarking consideration too. Unfortunately weather conditions as well as wind and rain can drive water under a shallow pitched roof if you don’t get it right.
Low roof angle – In a situation where you are building a new shallow sloping roof make sure someone makes an effort to measure the finished slope properly before its tiled or slated. There are even very good mobile phone apps that will do this for you these days, mistakes can be made whilst following plans.
Undersarking – Membrane or Felt
Undersarking provides a secondary line of defence against water ingress in exceptional circumstances and should NOT be relied upon to keep water out, the roof covering should do that 99.9% of the time.
Undersarking – The generic term used for a waterproofing layer underneath the top roof covering of tiles, slates, etc. Commonly breathable roofing membrane these days or sometimes under tillers or under slater’s felt called 1F is used.
If you have a shallow pitched roof only the best quality breathable roofing membrane should be used or 1F under felt or similar, ask roofing contractors about their recommendations for these situations.
Joining two roofs together
This will be necessary where your roof meets a neighbouring roof, sometimes you may need to join onto your neighbours roof or you may have an adjoining roof yourself that you wish to keep. This can occur when a slate roof meets tiles, artificial slates, different sized slates or your joining two non matching tile profiles.
Bonding gutter explained – If you are joining two different types of roof together you will need to used a special roof joint called a bonding gutter, this is also sometimes referred to as a secret gutter or secret valley.
Unfortunately some roofers do not fit these as they are time consuming to fit and time is money, so instead they join onto next doors roof with a simple overlap and a sand and cement mortar bed only. This is totally wrong and will leak after a few years if not straight away, it usually leads to expensive repairs and angry neighbours in my experience.
Joining two similar roofs together
Joining similar roofs – If you use similar sized or the same profiled tiles or slates it is possible to blend one roof into another, this will make life easier for the roofer and therefore cheaper for you.
Lead valleys
Lead valleys are a way of joining one roof to another or separating two roofs, and they should be treated exactly the same as lead flashings above. If you have lead valleys and your having a new roof do not re-use the old lead, it really is false economy. Especially if at a later stage you have to remove them and replace them.
Lead and GRP valleys compared – There’s very little difference to from floor level and both will last a very long time if well fitted.
Fibreglass GRP valleys
Fibreglass valleys are the modern alternative to lead, its not better but it is cheaper. With the average cost of milled lead at say £100 for a medium sized roof valley, a fiberglass valley the same size could cost as little as £10. Now if you imagine this saving scaled up, it goes some way to explaining why they are so popular on large new build housing estates. If you are going to use fibreglass valleys I would still recommend the roofer installs valley boards, should any one have to walk up, or work on the valley at a later stage, a foot will not shatter or go through the valley if is supported by valley boards.
Lead flashings
Check to see if you will be getting new roof flashings or lead flashings, all good roofers will renew them automatically, but on numerous occasions I have seen the old lead flashings from the previous roof re-used to save on lead costs and labour.
Typically a roofer could save a days labour plus lead costs by using the old lead flashings and soakers, but as they have already probably done a 50 to 100 years service its never a good idea to use them. Lead wears thin and splits with age, don’t use it again.
Roof ventilation
People living in houses generate warm moist air from every day living. Cooking, bathing and even breathing will all contribute to this, and it all wants to rise upwards or find a cold surface. Lofts can become damp and even mouldy it you don’t have sufficient air circulation and ventilation inside your roof space so don’t forget to ask your potential roofing contractors about roof vents or tile vents to combat this.
Ridge tiles or Bonnets
Ridge tiles or hip ridges sit on the top edges of a roof and provide a water proof capping between one elevation of a roof and another i.e. between a front and back roof.
These can be fixed in the traditional manner of sitting on a bed of strong mortar or via a newer dry ridge system. Dry ridge is a method of mechanical fixing by clips or screws that does not require a wet mortar mix, either technique if done correctly will provide many years of trouble free service.
Verges and Gable ends
Verges are the name given to finish at the end of a roof, most commonly seen at a gable end.
Gable end verges – Again there are two common types, the traditional mortar finish ( bedded verge ) or a newer dry verge system or cloaked verge. Both provide an excellent finish as long as they are done properly.
Anti pest measures
This is an important detail that sometimes get forgotten at the very bottom of a tiled roof ( eaves ). If you have any sort of roof tile with a profile that is not flat it may leave open ends for pests like birds or squirrels to get in.
Make sure bird combs or eaves fillers are used, and if you are prone to squirrels in your area ask a roofing contractor what he can recommend. Sometimes aluminium eaves fillers can be sourced or open tile profiles can be filled with mortar.
Planning permission
Do I need planning permission to change my roof ?
Yes and No. If your are re roofing with a similar material and not changing the structure of your roof you should be OK, as long at the new roof isn’t heavier, significantly lighter or different in such a manner that it could cause movement to occur. If you are changing from for instance Slate to Tiles, this could be one of those situations and advise should be sought. Also keep in mind that local planning may forbid the change of a particular roofing material like local stone, local slate or thatching for a modern material. Ask you local roofing contractor about these issues as he should know about any regulations specific to your area. Also see the advise on the planning portal
Sponsored Links
Also see…
- How to tile a roof
- Flat roof replacement guide – best flat roofs
- Flat roof costs – current flat roof prices
