[Step by Step] Is Your Terraced House Roof Space Is Suitable For A Loft Conversion?

Thinking of converting the attic in your terraced house into a liveable loft?

The bad news is that not not all attic spaces can be converted, at least converted inexpensively.

If your headroom is poor then you might need to replace the whole roof.

But before we go totally nuts we need to check it in the first place.

Well in this blog post I’ll show you how to check if you can convert your loft with a simple step by step method.

After this article you’ll know how much expense and hassle may be involved in comnverting your loft!

This is also affects your loft stairs access.

Loft conversions are an extremely economical way of getting a lot more space out of your Terraced House as they are one of the cheapest types of extension you can do providing your roof is suitable for one.

However it’s also worth saying now that with lofts we need to be a bit creative with how we plan them out.

Things like loft conversion stairs access, headroom, drainage & utilities can be tricky.

Loft conversions are a very efficient use of space in a property and you can often convert your loft under your permitted development rights as long as you are in a standard planning area.

What that means is you don’t require full planning permission as long as you don’t exceed 10% of the overall gross floor area of your home or no more than 50m³ of volume of an extension.

You still need permission from your local council but it’s a fast track process and the council can’t object to your loft conversion.

You will require full planning permission however if you intend on adding roof lights or adding dormer windows. This can be an issue if you live in a conservation area or listed building.

However before you go down that road you must check that a loft conversion is possible in the first place.

I’ve outlined below a 3 step check that will not only let you know if a loft conversion is possible but also what size loft you’ll have once the work is finished.

 Step 1: Roof Structure Check

You first need to check if you have a trussed roof or a cut timber roof. If your home was built pre-1960 then you most likely have a cut timber roof.

Here’s what a trussed roof looks like:

Here’s what a cut timber roof looks like:

They might look very similar but there is a big difference.

The trussed roof has been designed as one big structural system, if you remove one member then the whole frame falls apart.

So to convert a trussed roof into a usable loft space usually means replacing the entire roof structure.

The cut timber roof however, has been designed using very separate members so removing one member doesn’t cause the rest of the frame to fall apart.

And as a result we can move things around without having to replace the entire roof.

If you have a trussed roof then you’ll need to consult with a structural engineer as to the feasibility of modifying the roof structure to open up the space for a loft conversion.

If you have a cut timber roof then congratulations as these types of roof are far easier to modify to open up the loft space and give you loft stairs access.

 

Step 2: Check Pitch & Span Of The Roof

With this step you need to check the angle your roof slopes otherwise known as the pitch. And you also need to check the span of your roof which is the distance between the front and rear walls of your house.

To check the pitch all you need to do is get into your roof space with a protractor (remember these from your school geometry sets?) and measure the angle of the main rafters.

Another way is to measure back 1.0m from the inside face of your front or rear wall. Then mark that point with either marker or some spray paint. You then measure from that point to the underside of the main rafters above.

You can now use that dimension with the table below, we’ll call that dimension X:

Table 1: Pitch based on vertical dimension X from a point 1m back from inside face of wall to underside of main roof rafter

X	Pitch
0.70m	35°
0.84m	40°
1.00m	45°
1.19m	50°
1.43m	55°

These 2 dimensions will determine if you can get adequate head room and floor space in your loft.

Once you check both the pitch and the span then use this table below to see if you’ll be able to get a loft into the roof space or not:

Table 2: Possible Conversion Based on Pitch & Span

	Roof Span (m)
Roof Pitch	6.5m	7.0m	8.0m	8.5m	9.0m
35°	–	–	–	–	ok
40°	–	–	ok	ok	ok
45°	ok	ok	ok	ok	ok
50°	ok	ok	ok	ok	ok

Any spans greater than 9m that still have at least a 35° pitch pass this test.

 

Step 3: Internal Loft Dimension Check

Now that we have checked the roof structure and the overall dimensions of your roof, we now need to check if we have enough internal space in the loft.

There’s no point going to all the effort of building a loft conversion if we are going to end up with a tiny space when it’s finished!

Or have no headroom coming up your loft conversion stairs!

It is obvious that we can’t maintain a constantly straight roof when it comes to the inside of your loft. The sides will be sloped to match the existing roof slope. But we do need to trim this out with some ceiling and side walls to form the space.

So as a rule of thumb we want to have 2.3m headroom in the middle of the loft which will be under the apex of your roof and we want to construct 1.0m high side walls so we can comfortably sit low furniture against them.

So that all looks like this:

We will be using the space behind these low side walls for storage or to relocate your water tank.

You can using these dimension see just how much space there will be in your loft conversion.

Ok we haven’t allowed for bigger floor joists, roof insulation and the like but this does give you a very good ball park feel for the space you’ll get from your loft.

Other Considerations Such As Loft Stairs

Now that we’ve determined whether your roof space is suitable for a loft conversion there are some other things we need to take into account.

The first is the condition of the roof timbers.

If they are decayed or have been on the receiving end of insect attack then they will need to be replaced.

You will also need to cut some out to trim out an opening for your loft stairs.

The condition of the walls both external and internal will need to be checked if they need any repair.

The party wall with your neighbour will also need to be inspected for it’s condition.

If you have any internal load bearing walls in the floor below then these will be used to support the loft floor.

Drainage, water tanks and any other services will need to be re-routed so keep that in mind.

One more important consideration is the lintels over the top floor windows and these will need to be checked for their adequacy.

This is especially important if you have to use steel beams to support the loft.

This might happen if you have no internal load bearing walls and we need to put in some beams to support the modified roof structure.

But these are things your structural engineer will help you with any way.

I’m just making you aware of them.

So there you have a simple 3 step method of checking whether your roof space is suitable for a loft conversion.

So what do you think?

I’ve tried to make this blog post as un-techie as possible but if you need me to clarify anything please leave a comment below and I’ll address it.

Also if you have any other questions, requests for posts on specific topics or just liked what you read then please leave a comment below too.

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Want To Know How Much Your Loft Conversion Will Cost?

The most common question we get on this site and from our clients is “how do I get a ball park figure for my building work so I have an idea on how much it will cost me before I start?”

And there hasn’t really been an easy answer to that…

…until now!

Well if the question above also applies to you then you need to check out our Ultimate Loft Conversion Costing Toolkit.

Basically we’ve tried every costing tool both offline & online and we’ve put together this toolkit which shows you how to use what we consider the best 3 free online costing tools that exist for the UK market.

We break down each one and give you step-by-step instructions on how to use them and you’ll be shocked with how ridiculously easy to use they are.

We’ll also show you what info you need to fill them out and how to get this info if you don’t have it, again it’s really simple to do.

This is the best resource on the big bad interwebs for getting a pretty good ballpark figure for your loft conversion.

And the best part is that you can do it all online, there’s no calling anyone or booking an appointment or being hounded by sales people!

In summary:

• Discover the 3 free & super-simple online costing tools made for loft conversions
• Get an accurate cost for your potential loft conversion in 5 minutes or less, yes it’s really that fast!
• Make sure you don’t get over-priced and ripped off by builders on your dream loft

And this is just a sample!

So to find out more all you have to do is click the link below:

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